The abbreviation cf. (short for the , both meaning "compare") 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 word "see" be used to point to a source of information. Biological use 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, " cf. " indicates that the specimen is in the genus Barbus and believed to be , 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. 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 ", cf. ", 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. Numismatic use 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 is question is not an exact match but comes close to a known source, cf. may be used. See also Aff. Citation signal List of Latin abbreviations Viz. References External links Abbreviations Latin words and phrases