The phrasal verb "let in" is commonly used in both informal and formal contexts, though it tends to appear more in informal speech. It typically means to allow someone or something to enter a space, such as a building or a room, indicated by sentences like "Please let in the cat" or "Can you let me in?" This phrasal verb is particularly popular in everyday conversations but is also perfectly acceptable in written communication, especially in contexts related to admission or access. Additionally, "let in" can be extended metaphorically, such as with letting emotions or information be known to someone, like "let someone in on a secret." It is important not to confuse this with non-phrasal usage, where "let in" is used in a literal sense without forming a complete phrasal verb.
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1. To allow someone or something to enter a place.
She heard a knock on the door and went to let in her friend.
The guard let in the visitors after checking their IDs.
2. To allow someone to become a part of a group or organization.
The club decided to let in several new members this year.
They agreed to let in startups to the business networking event.