[This entry is taken from a chapter of Part II of the open-source textbook Spanish-English Cognates: An Unconventional Introduction to Spanish Linguistics.]
Lat. servāre and derived verbs
Eng. conserve ~ Sp. conservar
Eng. conserve [kənˈsɜɹv] was borrowed through French in the 14th century, and French borrowed it from Latin in the 9th century from Lat. consĕrvāre. Sp. conservar is first attested in the 13th century (Berceo), thought it is rare before the 15th century (DCEH). It is not known whether the author who introduced conservar into Spanish was borrowing it directly from written Latin or whether it was borrowing it through French, as was so often the case with such words.
English dictionaries vary as to how they define the meanings of Eng. conserve, but most agree that it has two major and closely related senses that can be defined as ‘protect from harm or destruction’ (COED), as in We must conserve our woodlands for future generations (LDCE), and ‘prevent the wasteful overuse of’ (COED), as in the need to conserve energy (LDCE). A few of the major English dictionaries mention other minor senses, such as for example ‘to preserve with sugar’ (MWC), a sense that is related to the derived noun conserve (see below).
Sp. conservar may also be used with both of those senses in some contexts, but there are major differences as well. The DLE gives 5 senses for conservar, all of which share the idea of preservation which is somewhat indirectly found in the senses of Eng. conserve. These are the five senses found in the DLE for conservar:
1 Maintain or take care of the permanence or integrity of something or someone. (also used pronominally)
2 Keep someone alive and unharmed.
3 Continue the practice of habits and customs.
4 Store something carefully, e.g. Conserva las joyas de su familia desde hace años ‘She has kept the jewels of his family for years’
5 Preserve food in a suitable environment, e.g. Conserva el queso en aceite ‘Keep/preserve the cheese in oil’
It is interesting to compare the entries for these verbs in two-way dictionaries. What we find is that they tend to give conservar as one of the options to translate the different senses of Eng. conserve, but they never (or hardly ever) give Eng. conserve as one of the possible ways to translate Sp. conservar. This is true of the Vox (Vox), Oxford (OSD), and Collins dictionaries, for example. Looking at the Vox dictionary, we are told in the English-Spanish section that Eng. conserve has three senses, all of which can be translated as conservar plus one other verb:
· conserve transitive verb
wildlife, etc) conservar, proteger [‘protect’]
2 (save) conservar, ahorrar [‘save’]
3 (resources) conservar, preservar [‘preserve’]
However, if we look in the same dictionary for the possible English translations for the various senses of the Spanish verb conservar in the same dictionary, we are told that it has six senses, four of which are transitive and two that are intransitive (pronominal-reflexive), none of which translates into English as conserve!
2 (mantener) to keep in, maintain
3 (guardar) to keep, save
aún conservo las entradas I still have the tickets
4 (enlatar) to tin, can
verbo pronominal conservarse [intransitive]
etc) to survive
2 figurado (mantenerse) to keep well
tu padre se conserva muy bien your father looks good for his age
This is a perfect example of how cognates are so rarely perfect ‘friends’ (interchangeable in all contexts), even when their core meanings seem to be quite close (cf. Part I, Chapter 1). The same thing is true of the nouns derived from these verbs in each of these languages: Eng. conserve and Sp. conserva. Eng. conserve, which some pronounce just like the verb, with final stress, [kənˈsɜɹv] and others pronounce with initial stress, as [ˈkɒnsəɹv], means ‘fruit that is preserved by being cooked with sugar’, as in strawberry conserve (LDCE). This meaning translates into Spanish as confitura or mermelada, although if the fruit is in large pieces it can be considered to be a conserva, which in English is more likely to be called preserves. Spanish conserva means primarily ‘tinned food, canned food’, which is typically not sweet, though not always.
 The original: ‘conservar Del lat. conservāre. 1. tr. Mantener o cuidar de la permanencia o integridad de algo o de alguien. U. t. c. prnl. 2. tr. Mantener vivo y sin daño a alguien. 3. tr. Continuar la práctica de hábitos y costumbres. 4. tr. Guardar con cuidado algo. Conserva las joyas de su familia desde hace años. 5. tr. Preservar un alimento en un medio adecuado. Conserva el queso en aceite’ (DLE).