Commonest

adjective

1. Mutual; shared by more than one.

   "The two competitors have the common aim of winning the championship."

2. Occurring or happening regularly or frequently; usual.

   "It is common to find sharks off this coast."

3. Found in large numbers or in a large quantity; usual.

   "It differs from the common blackbird in the size of its beak."

4. Simple, ordinary or vulgar.
5. (grammar) In some languages, particularly Germanic languages, of the gender originating from the coalescence of the masculine and feminine categories of nouns.