plural of flat back four

plural of gentleman of the back door

plural of green-backed firecrown

plural of mortgage-backed security

plural of olive-backed oriole

plural of rufous-backed antvireo

plural of Paschen-Back effect

(US, slang) The third row of seats in a station wagon, especially rear-facing.

(intelligence) To retrace events so as to determine where an operation went wrong and who was responsible. / (diplomacy) To back down; to adopt a position where one is more willing to compromise.

(idiomatic) Ready if needed, in reserve, prepared, available for use whenever it might be advantageous.