allograph
variant form of a grapheme
letter case
distinctive property of a letter in a bicameral alphabet (most notably the Latin, Greek, or Cyrillic ones); piece of information whether a letter grapheme is taller "upper case" or lower "lower case"
lunate sigma
archaic form of Greek letter sigma
uppercase letter
type of letter in some alphabets used for particular purposes
lowercase
letter which is smaller than the capital
variant form
encoded variation of an unified character in the universal character set standardized in Unicode/ISO/IEC 10646