From Longman Dictionary of Contemporary Englishbrake fluidˈbrake ˌfluid noun [uncountable] Tliquid used in certain kinds of brakes so that the different parts move smoothly
Examples from the Corpus
brake fluid• She had to stoop again for the case, and so she caught sight of the pool of brake fluid at once.• If poor quality replacements have been fitted they may react with the brake fluid. 