IPA: /ˈsiːtləs/
KK: /ˈsiːtləs/
Not having a seat or a place to sit.
The new bus design was seatless, making it easier for passengers to stand during their commute.
Seatless → It is formed from "seat" (from Old English "sǣte", meaning a place to sit) and "-less" (meaning without). The word "seatless" means without a seat or lacking a place to sit.
Think of 'seat' as a place to sit and '-less' meaning without — so 'seatless' describes a situation where there is no place to sit.