balai

broom; broomstick flown by witches; the last bus or train (at night); tail (of a bird of prey); brush (electrical contact)

“Elle a quarante balais” — She’s forty

Inherited from Old French balai, from earlier balain (“bundle of broom”, 12th c.), ultimately from Proto-Celtic *banatlo- (“broom plant”). It is uncertain whether the Celtic word passed into French through a Gaulish *balano- or rather through Middle Breton balain, balazn, from Old Breton balan. The latter appears more likely.