letter in WordNet English dictionary

1. the conventional characters of the alphabet used to represent speech
   "his grandmother taught him his letters"
   letter  letter of the alphabet  alphabetic character 
   
2. a written message addressed to a person or organization
   "mailed an indignant letter to the editor"
   letter  missive 
   
3. an award earned by participation in a school sport
   "he won letters in three sports"
   letter  varsity letter 
   
4. a strictly literal interpretation (as distinct from the intention)
   "he followed instructions to the letter"; "he obeyed the letter of the law"
   letter 
   
5. owner who lets another person use something (housing usually) for hire
   letter 
   

1. mark letters on or mark with letters
   letter 
   
2. set down or print with letters
   letter 
   
3. win an athletic letter
   letter