Meaning of LET in English

LET

(SUGGEST) [verb] [T + object + infinitive without to; not in past tenses] letting, past let - used to express a suggestion which includes you and the other person or people, or a request or order(formal) Let us consider all the possibilities.Let's go out to dinner, shall we?Let's not argue/(UK also) Don't let's argue.You can use let to show that you accept what is going to happen although you do not like it.Let him come and speak to me, I'm not scared of him.Let it rain, it won't spoil our afternoon.You can say 'let me' as a threat.Just let me hear you saying such a thing again and you'll be sorry!Don't let me catch you in here again!(specialized) When making a plan or calculating a number, you use let to introduce the purpose of the argument.Let a = 4, b = 5.Let's face it (= We should accept the truth), you're never going to be a great artist.You say let's see/let me see/let me think when you want to think carefully about something or are trying to remember.Next Saturday, let's see, that's when we're going to the theatre.The last time I spoke to her was, now let me think, three weeks ago.

Cambridge English vocab.      Кембриджский английский словарь.