Define low. low synonyms, low pronunciation, low translation, English dictionary definition of low. adj. low·er , low·est 1. a. Having little relative height; not high or tall: a low wall. b. Rising only slightly above surrounding surfaces: a low hill.
Things that are less than usual can be described with the adjective low. You might be low on gas in your car, for example, or wake up with a low amount of energy.