Sanskrit

Preposition

अपि • ‎(api)

1. (preposition with location) close by or to, within, before; adv. further, also, too; even (with {na} = Latin quidem); at least, however, but (between words, clauses and sentences, or after, r. before an emphasized word).
2. After numerals = all

   all the four castes, etc.

3. At the beginning of a sentence, it is a particle of interrogation.

Suffix

अपि • ‎(api)

1. With an optative it expresses hope, fear, or desire. -- {api ca} or {cApi} further, moreover. {api--api} (or {ca}) as well as. {api ca--ja cApi} rather than. {ye'pi--te'pi} they too--who. {yadyapi} however, although. {tathApi} even so, nevertheless.
2. Converts an interrogative into an indefinite.

References

• Cappeller, Carl A Sanskrit-English dictionary Bostin, Ginn and Co., 1891.