[n] something a little different from others of the same type; "an experimental version of the night fighter"; "an emery wheel is a modern variant of the grindstone"
[n] a variable quantity that is random
[n] an event that departs from expectations
[n] (biology) a group of organisms within a species that differ in trivial ways from similar groups; "a new strain of microorganisms"
[adj] differing from a norm or standard; "a variant spelling"