behind

The word “behind” means at or toward the back of something, or after it in time, position, or progress. In plain terms, at the back of, or lagging after, something — also a polite word for someone's bottom.

“Behind” is pronounced bih-HYND (/ˈbiːˌhaɪnd/ in IPA).

Here is “behind” used in a sentence: “The keys fell behind the sofa.”

Depending on how it is used, “behind” can be a preposition and a noun.

The word “behind” comes from Old English. From Old English behindan, built from be- plus "hind," an old word for the back part of something.

“Behind” is a very common word in modern English, usually learned at around the A1 level.

“Behind” has 3 distinct senses listed in this dictionary. The most common is: at or toward the back of something, or after it in time, position, or progress.

The main opposite is "in front of" for position, and "ahead of" for progress or time. If a chair is behind the desk, the opposite places it in front; if you are behind schedule, being ahead means you are early. "Before" can also serve as an opposite in the sense of order.

"Behind" is mainly about physical position or lagging progress — standing behind someone, or falling behind in a race. "After" is mainly about time or sequence — leaving after lunch. They overlap when talking about order, but "behind" adds a sense of being at the back or trailing, while "after" simply marks what follows.

Yes. Beyond physical position, "behind" often means falling short in time or progress — "behind schedule," "behind on the rent," or "falling behind at school." In this sense it describes being later or less advanced than expected, the opposite of being ahead or on track.