within

The word “within” means inside the physical limits of something. In plain terms, inside a place, time limit, or set of boundaries.

“Within” is pronounced wihth-IHN (/wɪðˈɪn/ in IPA).

Here is “within” used in a sentence: “The treasure was hidden within the castle walls.”

The opposite of “within” — its antonyms — are outside, outwith and without.

“Within” is a preposition.

The word “within” comes from Old English. From Old English wiþinnan, formed from with plus in.

“Within” is a very common word in modern English, usually learned at around the A2 level.

“Within” has 3 distinct senses listed in this dictionary. The most common is: inside the physical limits of something.

Both mean contained by something, and often they are interchangeable. "Inside" simply marks a position within an enclosure. "Within" can feel slightly more formal and is also used more freely for limits that are not physical, such as time, distance, or rules, as in "within an hour" or "within budget."

Yes. Besides marking physical space, "within" very commonly expresses a limit of time, meaning "before a period is over." "Reply within three days" means before three days have passed. This figurative use, covering time, distance, and limits like budgets or rules, is now more frequent than the purely physical sense.

The natural opposites are "outside" and "beyond," which place something past the limits rather than inside them. "Within the walls" contrasts with "outside the walls"; "within reach" contrasts with "beyond reach." Which opposite you choose depends on whether you mean physical space or a figurative limit.

"The keys are within the drawer" places them inside its physical limits. Figurative examples are just as common: "within the city limits," "within arm's reach," or "finish within the hour." Each shows something contained inside a boundary, whether that boundary is a space, a distance, or a length of time.