At least one Latin verb, and perhaps two, was derived from a verb of sitting by means of the prefix sub‑ ‘under’. It is not clear that there was a verb derived from Lat. sĕdēre by means of this prefix, namely subsĭdēre (subsĭdĕo, subsĭdēre). It does not appear in most Latin dictionaries, though some claim it existed and that it meant ‘to rest, stay, or remain in a place’. What we know for sure, is that there was a verb derived by the prefix sub‑ from sĕdēre’s companion verb sīdĕre ‘to sit, settle’, namely subsīdĕre. This verb meant ‘to sit down, crouch down, squat’, as well as ‘to sink down, settle down’. The verb’s principal parts were (present indicative) subsīdō (present infinitive) subsīdĕre, (perfect active) subsēdī, (passive participle/supine) subsĕssus.
This verb never made it into Spanish, either as a direct patrimonial descendant or as a loan. English, however, did acquire it in the late 17th century in the form subside. The original meaning of this word was ‘to sink down, fall to the bottom, precipitate’ (OED). The word subside came into the language presumably directly from written Latin subsĭdēre, not through French which, like Spanish, does not have a reflex of this verb. We should note, however, that there are two single, isolated attestations of an Old French verb soubseoir, now obsolete, meaning ‘to sink down’, from the late 14th and 15th centuries, a verb that is related to Old French seoir ‘to sit’, a patrimonial descendant of Lat. sĕdēre. Be that as it may, it does not seem to be the source of Eng. subside, however. Assuming that Latin is the source, however, the fact that the English verb subside is not taken from the passive participle subsĕssus of the Latin verb (which would have given us Eng. *subsess), but rather from a clipped form of the Latin infinitive subsĭdēre tells us that there is probably something else going on here, as we shall see.
The English verb subside [səb.ˈsaɪ̯d] today has different meanings or senses in different contexts. It is definitely a bit of a fancy word not used in colloquial speech. When speaking of a building or a road, the verb subside means ‘to gradually sink to a lower level’ (DOCE), but this meaning is rather rare (less fancy synonyms: sink back, settle, cave in, fall in, collapse, give way, drop down, etc.). Another rare or archaic meaning of this word is ‘to sink or settle down, as into a sofa’ (AHD) (less fancy synonyms: flop, sink, collapse; informal flump, plonk oneself, plop oneself). Most of the time the verb’s subject refers to a departure from a normal situation and the verb has a meaning such as ‘to become less intense, violent, or severe until things gets back to normal’. Said of water, and in particular flood water, subside means ‘it gradually goes underground or back to a normal level’ (DOCE), as in The floods finally subsided (less fancy synonyms: ebb, fall back, flow back, go down, get lower, abate, diminish). It is also used to refer to extreme weather conditions getting back to normal, as in The wind gradually subsided (cf. go down, get lower, abate, diminish). Finally, when said of a feeling, pain, a sound or anything else that we detect through our senses, t means ‘to gradually become less strong until it ends or stops’, as in Finally the laughter subsided or The pain in my head has not subsided yet (cf. let up, quiet down, ease (up), relent, die down, die out, peter out, taper off, lessen, remit, diminish, dwindle, weaken, fade, wane, ebb, slowly cease, come to a stop/end).
The appropriate Spanish translation of the verb subside depends on what it is that subsides. Speaking of land, a road or a building, hundirse may be used, a verb that literally means ‘to sink (down)’. And the ‘sink into a sofa’ sense may translate as dejarse caer, lit. ‘to let oneself (fall) down’. The other, more common meanings of Eng. subside may translate as amainar when speaking of a storm, rain, or wind; decrecer or bajar (de nivel) when speaking of flood waters; calmarse or disminuir when speaking of pain, anger, or excitement; remitir when speaking of a fever; and ir apagándose when speaking of things such as the sounds of applause or laughter.
As we said, French did not have a verb derived from Lat. subsīdĕre, but it did have a word subside, pronounced [syb.ˈzid] in Modern French, that comes indirectly from that verb, a cognate and the source of the English word subsidy. Fr. subside does not come directly from the Latin verb subsīdĕre, but rather from a noun derived from it, namely subsĭdĭum (sub‑sĭd‑ĭ‑um). This word was originally referred to ‘the troops stationed in reserve in the third line of battle (behind the principes)’, that is to say ‘reserve, auxiliary, or support troops, reinforcements’. From that meaning, it came to also mean, by extension, ‘support, assistance, aid, help, protection, etc.’ (CTL). The word subside is attested in French in the late 13th century, and even earlier in the century as succide, with the meaning ‘help, assistance, aid’. By the 14th century, the word had acquired a meaning ‘contribution, tax’, and, later on, ‘pension, monetary help’ granted by the state or the government.
Eng. subsidy [ˈsʌb.sɪ.di] is a late 14th century loanword from Old French subside or, actually, from the Anglo-Norman dialect of Old French, which spelled it subsidie. The main meaning of the English word subsidy today is ‘a sum of money granted from public funds’, which can be ‘to help an industry or business keep the price of a commodity or service low’, ‘to support an undertaking held to be in the public interest’ or, less commonly, for some other reason (COED).
The Spanish word subsidio [sub.ˈsi.di̯o], cognate of Eng. subsidy and Fr. subside, has been around since the 15th century. Although all three words involve transfer of money (monetary assistance), their meanings are not the same. As we saw, the meaning of meanings of the English and French words are not the same and the meaning of Spanish subsidio is more like that of its French counterpart, where the word most likely came from. The ‘tax’ meaning is secondary or archaic nowadays in Spanish, however, and the main meaning is ‘time-limited economic public assistance’, as in subsidio de paro/desempleo ‘unemployment compensation (US) or benefits (UK)’, and subsidio de enfermedad ‘sickness benefit’. The main meaning of Eng. subsidy, namely ‘money given to businesses’, translates into Spanish as subvención.
From the nouns that we have just seen, both English and Spanish developed verbs that meant something like ‘to give monetary assistance’. The two languages used different ways to derive the verb and so they cannot be said to have the same source or to be cognates. The English verb is subsidize, formed by adding the Latinate suffix ‑ize to the word subsidy (minus the final letter): subsidy + ‑ize → subsidize (subsid‑ize). The verb means ‘to support (an organization or activity) financially’ or ‘pay part of the cost of producing (something) to reduce its price’ (COED). From the past participle of this verb comes the very common adjective subsidized by conversion which means ‘having partial financial support from public funds’ (WN), as in subsidized public housing.
The Spanish verb derived from the noun subsidio is subsidiar, formed from the stem subsidi‑ of the noun subsidio (after removing the final inflectional ending ‑o), and the verbal infinitival inflectional ending ‑ar. This word is used with the meaning ‘to give assistance to a person’, reflecting the main meaning of the noun subsidio, but it can also be used as a synonym of subvencionar, a verb derived from the noun subvención (see. fn. dd above), the main translation of Eng. subsidy, and thus it can also mean ‘to give a subsidy (to a business or other entity)’.
There are adjectives related to the nouns Eng. subsidy ~ Sp. subsidio, namely Eng. subsidiary ~ Sp. subsidiario/a, both of which mean ‘serving to assist or supplement; auxiliary’ (AHD) or ‘less important than but related or supplementary to something’ (COED). Eng. subsidiary also has a derived meaning when speaking of a company, namely ‘controlled by a holding or parent company’. Actually, the adjective subsidiary can be used as a noun with the meaning ‘a company that is owned or controlled by another larger company’ (DOCE).
Eng. subsidiary and Sp. subsidiario/a are loanwords from Lat. subsĭdĭārĭus derived from Lat. subsĭdĭum by means of the first-second conjugation adjective-forming suffix ‑āri‑(us/a/um) (sub‑sĭd‑ĭ‑ārĭ‑us). In military language this word meant ‘of or belonging to a reserve, subsidiary’ and outside the military, ‘serving for support, subsidiary’ (L&S).
Spanish subsidiario is not a very common adjective, less so than its English cognate, and it is rather formal. It is used in formal expressions such as asignación subsidiaria ‘help allocation or allowance’. Eng. subsidiary much more commonly translates as secundario/a, complementario/a, or adicional (cf. the English cognates of these words, secondary, complementary, and additional, which are synonyms of the different senses of the word subsidiary). When referring to a firm that depends on a larger one, Eng. subsidiary translates as filial, which can also be used as a noun, just like subsidiary can. Sp. filial is a loanword from Lat. filĭālis, an adjective derived from the stem filĭ‑ of the noun filĭus ‘son’ or filĭa ‘daugher’, sourcewords of patrimonial Spanish hijo and hija (filĭ‑āl‑is).
Finally, there is in English a rare noun subsidence [səb.ˈsaɪ̯.dəns] that descends from a Latin noun derived from the verb subsīdĕre. It is a loanword from the first half of the 17th century. Eng. subsidence is attested already in 1607 with a meaning that is now obsolete, but by 1634 it was already being used with the meanings ‘to sink down or fall to the bottom; to precipitate’, said of suspended matter, and, said ‘of something swollen or inflated’, ‘to reduce, esp. so as to become flat’ (OED). Forty years later the word was being used to refer to the sinking of the ground or of buildings as well as a few others that parallel the several senses of the verb subside that we saw earlier. This word today just has primarily those last two meanings since it most commonly refers to ‘the process by which an area of land sinks to a lower level than the land surrounding it, or a building begins to sink into the ground’ (DOCE), though it has a few other technical uses that most English dictionaries do not even mention.
Eng. subsidence no doubt came from French subsidence ‘sediment’. The first attestation of French subsidence is from the mid-16th century or at least fifty years before it is first found in English. However, the ultimate source of this word is the Latin noun subsīdĕntĭa ‘a sinking down, a settling, sediment’. This noun was derived in a familiar way, since we have seen the process several times in this chapter. It comes from the regular stem subsīdĕnt‑ of the present participle subsīdēns ‘sinking’ of the verb subsīdĕre ‘to sink, etc.’, by the addition of the derivational suffix ‑ĭ‑a that creates abstract nouns (sub‑sīd‑ĕ‑nt‑ĭ‑a). Note that there is also a variant of the English word subsidence, namely subsidency, pronounced either [sʌb.ˈsaɪ̯.dən.sɪ] or [ˈsʌb.sɪ.dən.sɪ] according to the OED. This variant, produced with the variant ‑cy of the French ending ‑ce (see above) is now even less common than its doublet, though it is still found in a few of the more voluminous dictionaries. Its meaning is ‘the process of subsiding, settling, or sinking’ (Chambers).
Spanish too has borrowed this word as subsidencia, which is a highly technical term, more so than its English cognate, used primarily in geology. The DLE gives it as a technical equivalent of hundimiento ‘sinking’ with the meaning ‘sinking of the soil, caused by the underground cavities produced by mining extractions’. Other dictionaries do not mention mining as the only possible cause of the ground sinking and at least one dictionary, GDLEL, mentions additional uses in meteorology and medicine. In meteorology it means ‘the lowering of a large layer of air in an anticyclonic situation’ and in medicine ‘gradual disappearance of a disease’. There is little doubt that these last two senses are calques of technical uses of Eng. subsidence, uses that do not appear in most English dictionaries due to their technical nature.
Finally, we mentioned earlier in the section that it was unusual for a verb like subside that was presumably taken from Latin directly and not from French to be derived from the present stem, in this case subsĭd‑, and no the passive participle stem, which was subsess‑ (cf. Chapter 8, §184.108.40.206.3). Although at first one might have thought that the reason for this was the influence of the French word subside, which gave us Eng. subsidy in the late 14th century, this is unlikely because of the large difference in meaning between the two words. It is actually much more likely that the reason had something to do with the existing word subsidence in English, which had been borrowed at least fifty years before the verb subside appears in the early 17th century. One even suspects that subside is first and foremost a back formation of the noun subsidence, and not a loan from Lat. subsīdĕre, though this verb may have played a part on the meaning of the verb after the fact.
 Note that without the length markers on the vowels, the two infinitives look identical (homographic) and, as we said earlier, chances are the two source verbs came to be confused in spoken Latin once vowel length stopped being as clearly made as it had been.
 Because of the short ‑ĭ‑ in the root of the word subsĭdĭum, some give this word as coming from a second conjugation subsĭdēre, not from third conjugation subsīdĕre.
 Sp. subvención ultimately comes from Latin but most likely it came into Spanish from Fr. subvention ‘financial assistance granted for relief by the State or a private or public organization’, ‘grant, subsidy’, a word that first appeared in the late 13th century, when it was spelled subvencion. It comes from Late Latin subvĕntĭo (accusative singular: subvĕntĭōnem), a noun derived from the verb subvĕnīre ‘to support, assist, come to the aid of, rescue’, which is derived from the verb vĕnīre ‘to come’, source of Spanish patrimonial venir. English too borrowed the word subvention from Old French in the early 15th century. The word is rather formal and rare in Modern English, not like its Spanish counterpart, and its meaning is ‘a gift of money, usually from a government, for a special use’ (COED).
 The original definitions in the DLE is ‘Hundimiento paulatino del suelo, originado por las cavidades subterráneas producidas por las extracciones mineras’ and in the GDLEL, respectively: ‘Descenso de una capa de aire de gran extensión, en una situación anticiclónica’ and ‘Desaparición gradual de una enfermedad’.