Is an idiom which means: To get married
For example, my sister and her fiancé are tying the knot on Saturday the 12th of October.
They are not a traditional couple; they met online, she proposed to him, and their wedding invitation is a picture of two extinct birds, well-known as dodos. She’s wearing a 1950’s wedding dress and I think he’s wearing a tracksuit! They are using a vegan mobile catering service for the reception and they have asked all their guests not to buy presents but to bring a bottle instead. I mean, what’s all that about then?!
Inglés Málaga 