Terrance Said:

should I write my internship as a training or work experience on my cv/resume?

We Answered:

Write it in work experience part - and mention designation as internee or type of work as Internship.

What they want to know is that if you worked in formal setting.

And internship is very close to work experience.

Training is usually in a setting specific for training. When you are in an internship the main purpose there is not to train people. But to do business.

So better write it in Experience - mention in brackets (Internship)