Enallage (which is pronounced like 'an allergy' or 'analogy', IPA: /ɛn ˈæl ədʒ ɪ/) is a Figure of speech. It means "The substitution of one grammatical form for another, e.g. of sing[ular] for pl[ural], of present for past tense, etc." (OED). It is a rarely used term, which may be useful to you some day.