1the bulk (of sth) [sing] the main part of sth; most of sth (事物的)主要部份,大部份:
The bulk of the work has been done, so we should finish this week.这个活大部份已经干完,这个星期完成应当没问题。
2 [U] the size, quantity or weight of sth large (大型物件的)体积,数量,重量:
The cupboard isn't especially heavy -- it's its bulk that makes it hard to move.这个碗柜倒不重,只是体积大,要搬动并非易事。He slowly lifted his vast bulk out of the chair.他挪动着肥大的身躯,慢慢地从椅子站起来。
in bulk in large quantities 大量:
If you buy in bulk, it's 10% cheaper.大量购买,九折优待。