The Collaborative International Dictionary of English v.0.48:

Safety \Safe"ty\, n. [Cf. F. sauvet['e].]
   1. The condition or state of being safe; freedom from danger
      or hazard; exemption from hurt, injury, or loss.
      [1913 Webster]

            Up led by thee,
            Into the heaven I have presumed,
            An earthly guest . . . With like safety guided down,
            Return me to my native element.       --Milton.
      [1913 Webster]

   2. Freedom from whatever exposes one to danger or from
      liability to cause danger or harm; safeness; hence, the
      quality of making safe or secure, or of giving confidence,
      justifying trust, insuring against harm or loss, etc.
      [1913 Webster]

            Would there were any safety in thy sex,
            That I might put a thousand sorrows off,
            And credit thy repentance!            --Beau. & Fl.
      [1913 Webster]

   3. Preservation from escape; close custody.
      [1913 Webster]

            Imprison him, . . .
            Deliver him to safety; and return.    --Shak.
      [1913 Webster]

   4. (Amer. Football) the act or result of a ball-carrier on
      the offensive team being tackled behind his own goal line,
      or the downing of a ball behind the offensive team's own
      goal line when it had been carried or propelled behind
      that goal line by a player on the offensive tream; such a
      play causes a score of two points to be awarded to the
      defensive team; -- it is distinguished from touchback,
      when the ball is downed behind the goal after being
      propelled there or last touched by a player of the
      defending team. See Touchdown. Same as Safety
      touchdown, below.
      [Webster 1913 Suppl. +PJC]

   5. Short for Safety bicycle. [archaic]
      [Webster 1913 Suppl.]

   6. a switch on a firearm that locks the trigger and prevents
      the firearm from being discharged unintentionally; -- also
      called safety catch, safety lock, or lock. [archaic]
      [PJC]

WordNet (r) 3.0 (2006):

safety catch
    n 1: guard consisting of a locking device that prevents a weapon
         from being fired [syn: safety catch, safety lock]