Could anyone explain exactly what Def defines?

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Answer 1

Hi Mateusz Niewinski
Please put a brief of your query in question title. It will help others to know your question quickly.
Thanks ☺

Answer 2

a function.
a function can be called later in the program.
like the 'range' function, which is predefined.
it helps to orginise your code and shorten it. because a function can be called as many times as you need unlike copypasting code everywhere