资料来源 : Webster's Revised Unabridged Dictionary (1913)

Lead \Lead\, n.
   1. The act of leading or conducting; guidance; direction; as,
      to take the lead; to be under the lead of another.

            At the time I speak of, and having a momentary lead,
            . . . I am sure I did my country important service.
                                                  --Burke.

   2. precedence; advance position; also, the measure of
      precedence; as, the white horse had the lead; a lead of a
      boat's length, or of half a second.

   3. (Cards & Dominoes) The act or right of playing first in a
      game or round; the card suit, or piece, so played; as,
      your partner has the lead.

   4. An open way in an ice field. --Kane.

   5. (Mining) A lode.

   6. (Naut.) The course of a rope from end to end.

   7. (Steam Engine) The width of port opening which is
      uncovered by the valve, for the admission or release of
      steam, at the instant when the piston is at end of its
      stroke.

   Note: When used alone it means outside lead, or lead for the
         admission of steam. Inside lead refers to the release
         or exhaust.

   8. (Civil Engineering) the distance of haul, as from a
      cutting to an embankment.

   9. (Horology) The action of a tooth, as a tooth of a wheel,
      in impelling another tooth or a pallet. --Saunier.

   {Lead angle} (Steam Engine), the angle which the crank maker
      with the line of centers, in approaching it, at the
      instant when the valve opens to admit steam.

   {Lead screw} (Mach.), the main longitudinal screw of a lathe,
      which gives the feed motion to the carriage.