1 [mass noun] the mass or size of something large:residents jump up and down on their rubbish to reduce its bulk large size or shape:he moved quickly in spite of his bulk [count noun] a large mass or shape. [as modifier] large in quantity:bulk orders of over 100 copies roughage in food:potatoes supply energy, essential protein, and bulk cargo in an unpackaged mass such as grain or oil: [as modifier]:the port is specially designed for the largest dry bulk vessels Printing the thickness of paper or a book.
(the bulk of
) the greater part of something:the bulk of the traffic had passed
1treat (a product) so that its quantity appears greater than it is:traders were bulking up their flour with chalk [no object]
) build up flesh and muscle, typically in training for sporting events: he took dietary supplements to bulk up as he lifted weights
2combine (shares or commodities for sale):your shares will be bulked with others and sold at the best prices available
1(of goods) in large quantities and generally at a reduced price:retail multiples buy in bulk 2(of a cargo or commodity) not packaged; loose: sugar is imported in bulk and bagged on the island