- a letter of the alphabet that usually differs from its corresponding lowercase letter in form and height, as A, B, Q, and R as distinguished from a, b, q, and r: used as the initial letter of a proper name, the first word of a sentence, etc.
Also called capital.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for capital letter
If the capital-letter be retained where a prefix is put to a proper name, the hyphen is obviously necessary."Stops"</p>
Word Origin and History for capital letter
late 14c.; see capital (adj.). So called because it is at the "head" of a sentence or word.
Online Etymology Dictionary, © 2010 Douglas Harper