What is "to sit up"

Sit \Sit\, v. i. [imp. Sat( Sate, archaic); p. p. Sat ( Sitten, obs.); p. pr. & vb. n. Sitting.] [OE. sitten, AS. sittan; akin to OS. sittian, OFries. sitta, D. zitten, G. sitzen, OHG. sizzen, Icel. sitja, SW. sitta, Dan. sidde, Goth. sitan, Russ. sidiete, L. sedere, Gr. ???, Skr. sad. [root]154. Cf. Assess, Assize, Cathedral, Chair, Dissident, Excise, Insidious, Possess, Reside, Sanhedrim, Seance, Seat, n., Sedate, 4th Sell, Siege, Session, Set, v. t., Sizar, Size, Subsidy.]

1. To rest upon the haunches, or the lower extremity of the trunk of the body; -- said of human beings, and sometimes of other animals; as, to sit on a sofa, on a chair, or on the ground.

   And he came and took the book put of the right hand of him that sate upon the seat.
   --Bible (1551) (Rev. v. 7.)

   I pray you, jest, sir, as you sit at dinner.
   --Shak.

2. To perch; to rest with the feet drawn up, as birds do on a branch, pole, etc.

3. To remain in a state of repose; to rest; to abide; to rest in any position or condition.

   And Moses said to . . . the children of Reuben, Shall your brothren go to war, and shall ye sit here?
   --Num. xxxii. 6.

   Like a demigod here sit I in the sky.
   --Shak.

4. To lie, rest, or bear; to press or weigh; -- with on; as, a weight or burden sits lightly upon him.

   The calamity sits heavy on us.
   --Jer. Taylor.

5. To be adjusted; to fit; as, a coat sts well or ill.

   This new and gorgeous garment, majesty, Sits not so easy on me as you think.
   --Shak.

6. To suit one well or ill, as an act; to become; to befit; -- used impersonally. [Obs.]
   --Chaucer.

7. To cover and warm eggs for hatching, as a fowl; to brood; to incubate.

   As the partridge sitteth on eggs, and hatcheth them not.
   --Jer. xvii. 11.

8. To have position, as at the point blown from; to hold a relative position; to have direction.

   Like a good miller that knows how to grind, which way soever the wind sits.
   --Selden.

   Sits the wind in that quarter?
   --Sir W. Scott.

9. To occupy a place or seat as a member of an official body; as, to sit in Congress.

10. To hold a session; to be in session for official business; -- said of legislative assemblies, courts, etc.; as, the court sits in January; the aldermen sit to-night.

11. To take a position for the purpose of having some artistic representation of one's self made, as a picture or a bust; as, to sit to a painter. To sit at, to rest under; to be subject to. [Obs.] ``A farmer can not husband his ground so well if he sit at a great rent''. --Bacon. To sit at meat or To sit at table, to be at table for eating. To sit down.

    1. To place one's self on a chair or other seat; as, to sit down when tired.

    2. To begin a siege; as, the enemy sat down before the town.

    3. To settle; to fix a permanent abode.
       --Spenser.

    4. To rest; to cease as satisfied. ``Here we can not sit down, but still proceed in our search.'' --Rogers. To sit for a fellowship, to offer one's self for examination with a view to obtaining a fellowship. [Eng. Univ.] To sit out.

       1. To be without engagement or employment. [Obs.]
          --Bp. Sanderson.

       2. To outstay.

          To sit under, to be under the instruction or ministrations of; as, to sit under a preacher; to sit under good preaching.

          To sit up, to rise from, or refrain from, a recumbent posture or from sleep; to sit with the body upright; as, to sit up late at night; also, to watch; as, to sit up with a sick person. ``He that was dead sat up, and began to speak.''
          --Luke vii. 15.