Main definitions of -a in English

1Forming ancient or Latinized modern names of animals and plants.

2Forming names of oxides.

3Forming geographical names.

4Forming ancient or Latinized modern feminine forenames.

5Forming nouns from Italian, Portuguese, and Spanish.

1Forming plural nouns from Greek or Latin neuter plurals corresponding to a singular in -um or -on (such as addenda, phenomena).

2Forming plural nouns in names (often from modern Latin) of zoological groups.

1Of.

2Have.

3To.