[Vocabulary] Classwork

[usignolo]

Could you tell me how I should write the word "classwork?"
Classwork/class work or class-work.
Which of these variants are used more often?

Links to authoritative sources are encouraged.

If I have any mistakes in my question, correct it, please.
It's very important for me.
Thanks in advance,
Max.

[jlinger]

Any dictionary would be an authoriitative source.

It's one word, as is classroom and homework.

The evolution of these compound words occurs over time. I am sure it started as class work, then probably went to class-work, but certainly for the past half century at least it's been one word.