In linguistics, an adjunct is a type of adverbial illustrating the circumstances of the action. It expresses such relations as time, manner, place, frequency, reason and degree, i.e. it answers the questions: where, when, how and why. For example:

It's near Boston. (Place adjunct.)

He spoke calmly (manner adjunct), since he had all the time in the world (adjunct of reason).

In beer making and homebrewing, an adjunct is an ingredient other than water, barley, hops, and yeast. Typically, adjucts are used by beer companies to save money while still producing high alcohol levels (corn sugar is the most common adjunct). This usually is at the sacrifice of body and flavor. Most North American lagers are heavy in adjuct use and light to nil in flavor. Less typically, fruit, spices, honey, and wheat are used as flavoring adjuncts.