Real Dictionary

multiply
verb: When something multiplies or when you multiply it, it increases greatly in number or amount.

multiply in American English 1
to cause to increase in number, amount, extent, or degree
to increase in number, amount, extent, or degree; specif., to increase by procreation
intransitive verb: to grow in number, quantity, etc.; increase
transitive verb: to make many or manifold; increase the number, quantity, etc., of

multiply in American English 2
in multiple ways
adverb: in several or many ways; in a multiple manner; manifoldly

multiply in British English
verb: to increase or cause to increase in number, quantity, or degree