knifeboard

A board on which knives are cleaned or polished.

A way of arranging benches back to back, resembling a knifeboard; common on the open upper deck of early double-deck omnibuses and trams.

knifeboard seating

Arthur Smith, A Summer Idyll On 'busses' knifeboards stretch'd, / The City clerks all tongue-protruded lay.

An early bus with narrow, restrictive seating; a knifeboard bus.