Jag n.  [Written also jagg.]
  1.  A notch; a cleft; a barb; a ragged or sharp protuberance; a denticulation.
  Arethuss arose . . .
  From rock and from jag.   --Shelley.
     Garments thus beset with long jags.   --Holland.
  2.  A part broken off; a fragment.
  3.  Bot. A cleft or division.
  4. A leather bag or wallet; pl., saddlebags. [Scot.]
  5.  Enough liquor to make a man noticeably drunk; a small “load;” a time or case of drunkeness; -- esp. in phr. To have a jag on, to be drunk. [Slang, U. S. & Dial. Eng.]
  Jag bolt, a bolt with a nicked or barbed shank which resists retraction, as when leaded into stone.
  Jag, v. t.  [imp. & p. p. Jagged p. pr. & vb. n. Jagging ] To cut into notches or teeth like those of a saw; to notch. [Written also jagg.]
  Jagging iron, a wheel with a zigzag or jagged edge for cutting cakes or pastry into ornamental figures.
  Jag, n.  A small load, as of hay or grain in the straw, or of ore. [Prov. Eng. &  Colloq. U.S.] [Written also jagg.]