1. A genus (group) of ants of the family Formicidae (ants) and the subfamily Formicinae (ants), and in turn Formica's own type species is the European red wood ant Formica rufa.

Common names for this group are wood ant, mound ant, and field ant.

2. Social insects of the family Formicidae, characteristically having wings only in the males and fertile females and living in colonies that have complex social organizations.