What is "pillow of a plow"

Pillow \Pil"low\, n. [OE. pilwe, AS. pyle, fr. L. pilvinus.]

1. Anything used to support the head of a person when reposing; especially, a sack or case filled with feathers, down, hair, or other soft material.

   [Resty sloth] finds the down pillow hard.
   --Shak.

2. (Mach.) A piece of metal or wood, forming a support to equalize pressure; a brass; a pillow block. [R.]

3. (Naut.) A block under the inner end of a bowsprit.

4. A kind of plain, coarse fustian.

   Lace pillow, a cushion used in making hand-wrought lace.

   Pillow bier [OE. pilwebere; cf. LG. b["u]re a pillowcase], a pillowcase; pillow slip. [Obs.]
   --Chaucer.

   Pillow block (Mach.), a block, or standard, for supporting a journal, as of a shaft. It is usually bolted to the frame or foundation of a machine, and is often furnished with journal boxes, and a movable cover, or cap, for tightening the bearings by means of bolts; -- called also pillar block, or plumber block.

   Pillow lace, handmade lace wrought with bobbins upon a lace pillow.

   Pillow of a plow, a crosspiece of wood which serves to raise or lower the beam.

   Pillow sham, an ornamental covering laid over a pillow when not in use.

   Pillow slip, a pillowcase.