The term "brew" has several meanings, depending on its context.
1) In a general sense, it can refer to any liquid that is prepared by soaking or steeping something in water, such as tea or coffee.
2) It can also be used to describe the process of making alcoholic drinks, such as beer or wine, by fermenting grains or fruits.
3) In a more specific sense, "brew" can refer to a particular type of beverage that is made from malted barley and hops, typically served in a glass with foam on top - this would be the definition used when referring to beer.