noun, の adjective
A sit seat is probably going to be a seat.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
This seat's cushion is really comfy.
I didn't know that I had to make reservations for seats.
The moment Salmon leaned across the seat to kiss Fugu in the car, the traffic light turned green.