15-Letter Words Containing: A,A,C,E,E,E

• A coffee klatch.

• extinct primitive toothed bird of the Jurassic period having a long feathered tail and hollow bones; usually considered the most primitive of all birds

• the 400th anniversary (or the celebration of it)

• A line, verse, or word that comprises eleven syllables.

• (mathematics, logic) such that the arguments or roles can be interchanged

• capable of replacing or changing places with something else; permitting mutual substitution without loss of function or suitability

• not open to challenge