white horse noun5 •A wave that is blown by the wind such that its crest is broken up and appears white and foamy; a whitecap. •Any of several horse-shaped chalk figures in England, such as the Uffington White Horse. •(slang) A recreational drug in the form of white powder: heroin or cocaine. •A large mass of tough sinewy substance in the head of sperm whales, just above the upper jaw and extending in streaks into the junk above it. It resembles blubber, but contains no oil. •(Singapore, disapproving) A soldier who is the child of a minister, high-ranking civil servant or officer, or comes from a highly influential family, who may receive preferential treatment from superiors. formswhite horses