Source : Webster's Revised Unabridged Dictionary (1913)

   {Capital letter} [F, lettre capitale] (Print.), a leading or
      heading letter, used at the beginning of a sentence and as
      the first letter of certain words, distinguished, for the
      most part, both by different form and larger size, from
      the small (lower-case) letters, which form the greater
      part of common print or writing.

   {Small capital letters} have the form of capital letters and
      height of the body of the lower-case letters.

   {Capital stock}, money, property, or stock invested in any
      business, or the enterprise of any corporation or
      institution. --Abbott.

   Syn: Chief; leading; controlling; prominent.

Source : WordNet®

capital letter
     n : one of the large alphabetic characters used as the first
         letter in writing or printing proper names and sometimes
         for emphasis; "printers once kept the type for capitals
         and for small letters in separate cases; capitals were
         kept in the upper half of the type case and so became
         known as upper-case letters" [syn: {capital}, {upper case},
          {upper-case letter}, {majuscule}] [ant: {small letter}]