To allow or permit someone or something to do something. verb
She let him borrow her car for the weekend.
Please let me know if you need any help.
To cause or make something happen. verb
The rain let the ground become muddy.
Let the cake cool before serving.
To lease or rent out a property to someone. verb
They decided to let their apartment while they were abroad.
The cottage is let to tourists during the summer months.
A hindrance or obstacle in a particular context, especially in sports like tennis, where a serve that hits the net and lands in the correct service box is replayed. noun
The serve was called a let, and the player had to serve again.
There was a let during the match, so the point was replayed.