Used other than figuratively or idiomatically: see at the back, in the depths. / deep down, in the end / deep down, at bottom, at heart

(tennis) baseline

(physics, astronomy) cosmic microwave background

(cosmetics) foundation

(theater) backdrop, background, backcloth (painted scenery at the back of a stage) / (figuratively) backdrop, background

(informal, figuratively) to hit rock bottom, to hit the rocks, to bottom out

Alternative spelling of para-ski de fond

(figuratively) to be a good person at heart, to be basically a good person, to have one's heart in the right place

(film) background noise

plural of bruit de fond