What does == mean ?

Answer 1

It is a comparison operator. It returns true, if both values are the same, otherwise false
Example:
5 == 5 //true
5 == 4 //false
5 == "5" //true, works for different datatypes

Answer 2

Sure, but he didn't say a word about languages

Answer 3

In Python 5 == "5" is False.
== is used to check, whether 2 compared values have the equal value and returns a boolean (True or False).
== in words: "is equal to".

Answer 4

Airree for the last example, I don't agree. In some langages, like JS, you're right but in python, it returns False.