open

The word “open” means not closed, blocked, or sealed — allowing entry, passage, or view. In plain terms, not shut — able to let things or people through, or, for a person, willing to share and communicate freely.

“Open” is pronounced OH-puhn (/ˈoʊ.pən/ in IPA).

Here is “open” used in a sentence: “She left the window open to let in some air.”

Words with a similar meaning to “open” include accessible, unimpeded and unseal.

The opposite of “open” — its antonyms — are closed, shut, without prejudice, checked and closed-source.

Depending on how it is used, “open” can be an adjective, a verb and a noun.

The word “open” comes from Old English. From Old English open, going back to a very old Germanic root meaning "up from under" — related to the English word "up.".

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

The most common opposite is 'closed' or 'shut.' Depending on context, 'sealed,' 'blocked,' or 'locked' also contrast with open. Where open allows entry, passage, or view, these words describe something stopped or fastened — a shut door, a sealed envelope, or a blocked road.

'Ajar' means slightly or partly open, and is used almost only of doors and windows — 'the door was ajar.' 'Open' is broader: it can mean fully open or simply not closed, and applies to almost anything, from a box to a road to a shop.

As an adjective, 'open' can describe something physically not closed (an open window), a business ready to serve customers (open till nine), something available or unrestricted (open to everyone), or a person who is frank and receptive (open-minded). Context decides which sense applies.