cf.

cf. is an abbreviation for the Latin word confer, meaning "compare" or "consult". It is mainly used in common and statute law contexts as well as in academic writing.

It is sometimes used (primarily in dictionaries) to imply insight into the preceding word's etymology — that is, to suggest how one term obtained its particular naming convention (perhaps from another phrase). For example, the phrase "Big Whack (cf. Big Bang)" suggests to the reader that the usage of the moniker (self given nickname) Big Whack derives at least its name from the latter.

In the system of binomial nomenclature, the use of "cf." is similarly used to indicate that the species need be seen in context of its comparison to another, but by definition is not confirmed as the same. For example Corvus cf. splendens indicates "a bird similar to the House Crow but not certainly identified as this species". For this reason many mistakenly believe that "cf" is an abbreviated form of "confirmed" or "inconfirmatus" or the like.