behind

Behind is a multi-function word in English. As a preposition, it indicates location at the rear of something: The shed is behind the fence. As an adverb, it can describe lateness or a backward movement in time: We are behind schedule, and the project fell behind. As a noun (informal), behind refers to the buttocks: She kept turning around to glance at her behind. The word also appears in many idioms, such as behind the scenes, behind the times, and behind someone’s back.

Etymology: Behind comes from Old English behindan, formed with the prefix be- and hind means “back.” Related forms exist in other Germanic languages (for example, German hinter, Dutch achter). The core sense is position at the rear, with later extensions to concepts of delay, support, or secrecy.

Usage notes: Prepositions vs. adverbs: behind introduces a noun phrase when it expresses location (behind the house), but it can function as an adverb when paired with a verb or adjective to express lateness or relative movement (behind schedule; fall behind). Common idioms include behind someone’s back (without their knowledge), behind the scenes (in private operations), and behind the times (outdated). It can also mean support or backing for a person or cause (to be behind a candidate) and financial arrears (to be behind on payments).

See also: behind the scenes, behind schedule, behind someone’s back.