The abbreviation cf. (short for either Latin Latin: confer or Latin: conferatur, both meaning 'compare')[1] is used in writing to refer the reader to other material to make a comparison with the topic being discussed. Style guides recommend that "cf." be used only to suggest a comparison, and the words "see" or "vide" be used generally to point to a source of information.[2] [3] In Italian, the abbreviation "cfr." (confronta, 'confront') is more common than "cf." is.[4]
See main article: Open nomenclature. In biological naming conventions, cf. is commonly placed between the genus name and the species name to describe a specimen that is hard to identify because of practical difficulties, such as poor preservation. For example, "Latin: Barbus cf. Latin: holotaenia" indicates that the specimen is in the genus Barbus and believed to be Latin: [[Barbus holotaenia]], but the actual species-level identification cannot be certain.
Cf. can also be used to express a possible identity, or at least a significant resemblance, such as between a newly observed specimen and a known species or taxon.[5] Such a usage might suggest a specimen's membership of the same genus or possibly of a shared higher taxon. For example, in the note "Latin: Diptera: Tabanidae, cf. Latin: Tabanus", the author is confident of the order and family (Diptera: Tabanidae) but can only suggest the genus (Tabanus) and has no information favouring a particular species.[6]
Among numismatists (coin collector-research specialists), cf. may be used in references on the paper and/or online coin identification information meaning "compare to". It is common for abbreviations of listings in trusted coin catalogues or sales from certain online auctions to be cited when identifying a particular coin. If the specimen in question is not an exact match but comes close to a known source, cf. may be used.