What is "companion hatch"

Hatch \Hatch\, n. [OE. hacche, AS. h[ae]c, cf. haca the bar of a door, D. hek gate, Sw. h["a]ck coop, rack, Dan. hekke manger, rack. Prob. akin to E. hook, and first used of something made of pieces fastened together. Cf. Heck, Hack a frame.]

1. A door with an opening over it; a half door, sometimes set with spikes on the upper edge.

   In at the window, or else o'er the hatch.
   --Shak.

2. A frame or weir in a river, for catching fish.

3. A flood gate; a sluice gate.
   --Ainsworth.

4. A bedstead. [Scot.]
   --Sir W. Scott.

5. An opening in the deck of a vessel or floor of a warehouse which serves as a passageway or hoistway; a hatchway; also; a cover or door, or one of the covers used in closing such an opening.

6. (Mining) An opening into, or in search of, a mine.

   Booby hatch, Buttery hatch, Companion hatch, etc. See under Booby, Buttery, etc.

   To batten down the hatches (Naut.), to lay tarpaulins over them, and secure them with battens.

   To be under hatches, to be confined below in a vessel; to be under arrest, or in slavery, distress, etc.

Companion \Com*pan"ion\ (k[o^]m*p[a^]n"y[u^]n), n. [F. compagnon, OF. compaing, fr. an assumed LL. companio (cf. companium fellowship, a mess), fr. L. com- + panis bread. See Pantry.]

1. One who accompanies or is in company with another for a longer or shorter period, either from choice or casually; one who is much in the company of, or is associated with, another or others; an associate; a comrade; a consort; a partner.

   The companions of his fall.
   --Milton.

   The companion of fools shall smart for it.
   --Prov. xiii. 20 (Rev. Ver.).

   Here are your sons again; and I must lose Two of the sweetest companions in the world.
   --Shak.

   A companion is one with whom we share our bread; a messmate.
   --Trench.

2. A knight of the lowest rank in certain orders; as, a companion of the Bath.

3. A fellow; -- in contempt. [Obs.]
   --Shak.

4. [Cf. OSp. compa[~n]a an outhouse, office.] (Naut.)

   1. A skylight on an upper deck with frames and sashes of various shapes, to admit light to a cabin or lower deck.

   2. A wooden hood or penthouse covering the companion way; a companion hatch.

      Companion hatch (Naut.), a wooden porch over the entrance or staircase of the cabin.

      Companion ladder (Naut.), the ladder by which officers ascend to, or descend from, the quarter-deck.
      --Totten.

      Companion way (Naut.), a staircase leading to the cabin.

      Knights companions, in certain honorary orders, the members of the lowest grades as distinguished from knights commanders, knights grand cross, and the like.

      Syn: Associate; comrade; mate; compeer; partner; ally; confederate; coadjutor; accomplice.