Vine's Expository Dictionary of NT Words 
from kata, "down," and hedra, "a seat," denotes "a seat" (Eng., "cathedral"), "a chair," Matthew 21:12; Mark 11:15; of teachers, Matthew 23:2 .
"the first seat," Matthew 23:6; Mark 12:39; Luke 11:43; 20:46; see Chief , No. 6. Cp. ROOM.
"to sit, be seated," is translated "shall ... be seated" in Luke 22:69 , RV; "is seated," Colossians 3:1 , RV (AV, "shall ... sit" and "sitteth"). See Sit.
Webster's Dictionary 
(1): ( v. i.) To rest; to lie down.
(2): ( v. t.) To settle; to plant with inhabitants; as to seat a country.
(3): ( v. t.) To cause to occupy a post, site, situation, or the like; to station; to establish; to fix; to settle.
(4): ( n.) Posture, or way of sitting, on horseback.
(5): ( n.) A part or surface on which another part or surface rests; as, a valve seat.
(6): ( n.) 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.
(7): ( n.) 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.
(8): ( v. t.) To put a seat or bottom in; as, to seat a chair.
(9): ( v. t.) To assign a seat to, or the seats of; to give a sitting to; as, to seat a church, or persons in a church.
(10): ( v. t.) To fix; to set firm.
(11): ( v. t.) To place on a seat; to cause to sit down; as, to seat one's self.
(12): ( n.) 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.
(13): ( n.) 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.
King James Dictionary 
SEAT, n. L. sedes, situs.
1. That on which one sits a chair, bench, stool or any other thing on which a person sits.
Christ--overthrew the tables of the money changers and the seats of them that sold doves. Matthew 21 .
2. The place of sitting throne chair of state tribunal post of authority as the seat of justice judgment-seat. 3. Mansion residence dwelling abode as Italy the seat of empire. The Greeks sent colonies to seek a new seat in Gaul.
In Albe he shall fix his royal seat. Dryden.
4. Site situation. The seat of Eden has never been incontrovertibly ascertained. 5. That part of a saddle on which a person sits. 6. In horsemanship, posture or situation of a perosn on horseback. 7. A pew or slip in a chruch a place to sit in. 8. The place where a thing is settled or established. London is the seat of business and opulence. So we say, the seat of the muses,the seat of arts, the seat of commerce.
1. To place on a seat to cause to sit down. We seat ourselves we seat our guests.
The guests were no sooner seated but they entered into a warm debate.
International Standard Bible Encyclopedia 
sēt : This word is used to translate the Hebrew words ( מושׁב , mōshābh , שׁבת , shebheth , כּסּא , kiṣṣē' , and תּכוּנה , tekhūnāh ), once ( Job 23:3 ). It translates the Greek word (καθέδρα , kathédra ) ( Matthew 21:12; Matthew 23:2; Mark 11:15 ), and "chief seat" translates the compound word (πρωτοκαθεδρία , prōtokathedrı́a ) ( Matthew 23:6; Mark 12:39; Luke 20:46 ). In the King James Version it translates (θρόνος , thrónos ) ( Luke 1:52; Revelation 2:13; Revelation 4:4; Revelation 11:16; Revelation 13:2; Revelation 16:10 ), which the Revised Version (British and American) renders "throne." It denotes a place or thing upon which one sits, as a chair, or stool ( 1 Samuel 20:18; Judges 3:20 ). It is used also of the exalted position occupied by men of marked rank or influence, either in good or evil ( Matthew 23:2; Psalm 1:1 ).
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
Bibliography Information McClintock, John. Strong, James. Entry for 'Seat'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/s/seat.html. Harper & Brothers. New York. 1870.