Source : Webster's Revised Unabridged Dictionary (1913)

First \First\, a. [OE. first, furst, AS. fyrst; akin to Icel.
   fyrstr, Sw. & Dan. f["o]rste, OHG. furist, G. f["u]rst
   prince; a superlatiye form of E. for, fore. See {For},
   {Fore}, and cf. {Formeer}, {Foremost}.]
   1. Preceding all others of a series or kind; the ordinal of
      one; earliest; as, the first day of a month; the first
      year of a reign.

   2. Foremost; in front of, or in advance of, all others.

   3. Most eminent or exalted; most excellent; chief; highest;
      as, Demosthenes was the first orator of Greece.

   {At first blush}. See under {Blush}.

   {At first hand}, from the first or original source; without
      the intervention of any agent.

            It is the intention of the person to reveal it at
            first hand, by way of mouth, to yourself. --Dickens.

   {First coat} (Plastering), the solid foundation of coarse
      stuff, on which the rest is placed; it is thick, and
      crossed with lines, so as to give a bond for the next
      coat.

   {First day}, Sunday; -- so called by the Friends.

   {First floor}.
      (a) The ground floor. [U.S.]
      (b) The floor next above the ground floor. [Eng.]

   {First} {fruit or fruits}.
      (a) The fruits of the season earliest gathered.
      (b) (Feudal Law) One year's profits of lands belonging to
          the king on the death of a tenant who held directly
          from him.
      (c) (Eng. Eccl. Law) The first year's whole profits of a
          benefice or spiritual living.
      (d) The earliest effects or results.

                See, Father, what first fruits on earth are
                sprung From thy implanted grace in man!
                                                  --Milton.

   {First mate}, an officer in a merchant vessel next in rank to
      the captain.

   {First name}, same as {Christian name}. See under {Name}, n.
      

   {First officer} (Naut.), in the merchant service, same as
      {First mate} (above).

   {First sergeant} (Mil.), the ranking non-commissioned officer
      in a company; the orderly sergeant. --Farrow.

   {First watch} (Naut.), the watch from eight to twelve at
      midnight; also, the men on duty during that time.

   {First water}, the highest quality or purest luster; -- said
      of gems, especially of diamond and pearls.

   Syn: Primary; primordial; primitive; primeval; pristine;
        highest; chief; principal; foremost.

Source : WordNet®

first floor
     n : the floor of a building that is at or nearest to the level
         of the ground around the building [syn: {ground floor}, {ground
         level}]