You can refer to something's bulk when you want to emphasize that it is very large.
例句
The truck pulled out of the lot, its bulk unnerving against the dawn.卡車從空地上開出來，龐大的車身小心翼翼地避讓著草坪。...the shadowy bulk of an ancient barn.一座古老谷倉的巨大陰影
N-SING
龐大的身軀；巨大的體重；肥碩的體形
You can refer to a large person's body or to their weight or size as their bulk .
例句
Bannol lowered his bulk carefully into the chair...班諾爾小心翼翼地將肥碩的身軀落座到椅子上。Despite his bulk he moved lightly on his feet.盡管他身形龐大，移動起來還是很靈巧。
QUANT
主體；大部分
The bulk of something is most of it.
例句
The bulk of the text is essentially a review of these original documents...文章的主要部分基本是對這些原始文件的回顧。The vast bulk of imports and exports are carried by sea.大部分的進出口貨物都是通過海路運輸的。
N-UNCOUNT
大宗，大批（買賣）
If you buy or sell something in bulk, you buy or sell it in large quantities.
例句
Buying in bulk is more economical than shopping for small quantities.批量采購要比零買實惠很多。...bulk purchasing.大宗采購