A seat, which could refer to any form of place to sit, with the distinction that a seat is generally fixed, and is not a chair which can be moved.
This emoji is intended to be a seat on some form of mass-transit, such as on an airplane, train or bus. Google previously displayed this as an orange wooden chair.
📅 Seat was approved as part of Unicode 6.0 in 2010
and added to Emoji 1.0 in 2015.