variant

an event that departs from expectations

(biology) a group of organisms within a species that differ in trivial ways from similar groups; "a new strain of microorganisms"

a variable quantity that is random

something a little different from others of the same type; "an experimental version of the night fighter"; "a variant of the same word"; "an emery wheel is the modern variation of a grindstone"; "the boy is a younger edition of his father"

differing from a norm or standard; "a variant spelling"

exhibiting variation and change; "letters variant in size"