Meaning of -AN in English

-AN

■ suffix

1》 forming adjectives and nouns, especially from:

↘names of places: Cuban.

↘names of systems: Anglican.

↘names of zoological classes or orders: crustacean.

↘names of founders: Lutheran.

2》 Chemistry forming names of organic compounds, chiefly polysaccharides: dextran.

Origin

from L. ~us , ~a , ~um .

Concise Oxford English vocab.      Сжатый оксфордский словарь английского языка.