What is "seat worm"

Seat \Seat\ (s[=e]t), n. [OE. sete, Icel. s[ae]ti; akin to Sw. s["a]te, Dan. s[ae]de, MHG. s[=a]ze, AS. set, setl, and E. sit. [root]154. See Sit, and cf. Settle, n.]

1. The place or thing upon which one sits; hence; anything made to be sat in or upon, as a chair, bench, stool, saddle, or the like.

   And Jesus . . . overthrew the tables of the money changers, and the seats of them that sold doves.
   --Matt. xxi. 1

2. 2. The place occupied by anything, or where any person or thing is situated, resides, or abides; a site; an abode, a station; a post; a situation.

   Where thou dwellest, even where Satan's seat is.
   --Rev. ii. 1

3. He that builds a fair house upon an ill seat committeth himself to prison.
   --Bacon.

   A seat of plenty, content, and tranquillity.
   --Macaulay.

   3. That part of a thing on which a person sits; as, the seat of a chair or saddle; the seat of a pair of pantaloons.

4. A sitting; a right to sit; regular or appropriate place of sitting; as, a seat in a church; a seat for the season in the opera house.

5. Posture, or way of sitting, on horseback.

   She had so good a seat and hand she might be trusted with any mount.
   --G. Eliot.

6. (Mach.) A part or surface on which another part or surface rests; as, a valve seat.

   Seat worm (Zo["o]l.), the pinworm.