莚席 is read as えんせき (enseki) and means matting.
えんせき
enseki
しゅせき
head
しゅっせき
attendance
せき
seat
ざせき
きゃくせき
audience
けっせき
absence
そくせき
extempore
よせ
entertainment hall (for rakugo, manzai, magic, music, etc.)
ちゃくせき
taking a seat
banquet
ぎせき
parliamentary seat
どうせき
same (seating) precedence