pillar box

a pillarlike box in which letters are deposited for collection by mail carriers; mailbox.

Also called pillar post.

Origin of pillar box

First recorded in 1855–60

The letter was finished, and Guy went out to drop it in the pillar-box.

Guy and Pauline |Compton Mackenzie
Drop that letter into the pillar-box and you will be worried by no more Asprays.

Girls of the True Blue |L. T. Meade
To post the letter was the work of a minute or two, for there was a pillar-box a little way down the road.

My Friend Smith |Talbot Baines Reed
And yet she still stood staring at the slit in the pillar-box.

The Nest, The White Pagoda, The Suicide, A Forsaken Temple, Miss Jones and The Masterpiece |Anne Douglas Sedgwick

The others had all posted their letters in the pillar-box just outside our gate.

New Treasure Seekers |E. (Edith) Nesbit

pillar box

(in Britain) a red pillar-shaped public letter box situated on a pavement

characteristic of a pillar box (in the phrase pillar-box red)