What is the name of such a class implementation principle?

Question

OOP

What's the name of the concept of creating classes where all (almost) methods return a reference to themselves?
Example:

VK1.Messages.Send.PeerId(MessageData.PeerId).Message('Тест - ответ').Send;

or

TSQLSelect.Create.Ref
    .Fields([oIPerson.Fields])
    .From(oIPerson.Table)
    .Build;

I'm building such classes, but I don't remember the name of the method. For some reason Google doesn't help. Probably not what I'm asking.

Answer 1

fluent interface ?