D defs.my
Entry 3 senses Webster, 1913

Carrier

/kăr'-ē-ẽr/ · Car·ri·er · IPA /ˈkæɹ.ɪ.ə/
01 n. One who, or that which, carries or conveys; a messenger.
  1. 1.
    One who, or that which, carries or conveys; a messenger.
    “The air which is but . . . a carrier of the sounds.” Bacon.
  2. 2.
    One who is employed, or makes it his business, to carry goods for others for hire; a porter; a teamster.
    “The roads are crowded with carriers, laden with rich manufactures.” Swift.
  3. 3.
    That which drives or carries; as: (a) A piece which communicates to an object in a lathe the motion of the face plate; a lathe dog. (b) A spool holder or bobbin holder in a braiding machine. (c) A movable piece in magazine guns which transfers the cartridge to a position from which it can be thrust into the barrel.(Mach.)
Phrases & compounds
Carrier pigeon — a variety of the domestic pigeon used to convey letters from a distant point to to its home.
Carrier shell — a univalve shell of the genus Phorus; -- so called because it fastens bits of stones and broken shells to its own shell, to such an extent as almost to conceal it.
Common carrier — See under Common, a.