letters (Noun) — The literary culture. ex. "this book shows American letters at its best"
letters (Noun) — Scholarly attainment. ex. "he is a man of letters"
letters (Noun) — A written message addressed to a person or organization. ex. "mailed an indignant letter to the editor"
letters (Noun) — A character of the alphabet used in writing. ex. "his grandmother taught him his letters"
letters (Noun) — Owner who lets another person use something (housing usually) for hire.
letters (Noun) — A strictly literal interpretation (as distinct from the intention). ex. "he followed instructions to the letter" ex. "he obeyed the letter of the law"
letters (Noun) — An award earned by participation in a school sport.
letters (Verb) — Win an athletic letter.
letters (Verb) — Set down or print with letters.
letters (Verb) — Mark letters on or mark with letters.