Purpose of ～とは in 「あなたにとって仕事とはなんでしょうか」

Question

あなたにとって仕事【しごと】とはなんでしょうか

What is the purpose of とは above?
Would using は alone have been any different?

If とは is a grammatical construct, I would appreciate additional examples clarifying its significance.

Answer 1

“とは” introduces a definition.

“AとはBである” = “The definition of A is B”

In your example: “あなたにとって仕事 とは なんですか” = “How do you define jobs?” where “What do you work for?” is implied.

“あなたにとって仕事 は なんですか” sounds awkward and is interpreted as “あなたの仕事はなんですか” (= “What is your job?”).