Is topical tretinoin a steroid? Is it safe to use long-term?

I would like to move to a stronger retinol and want to use tretinoin (for aging skin/wrinkles). However, I was told that tretinoin is a steroid and should not be used long-term. I understood that it is a vitamin A derivative and is supposed to be used long-term for the best effects. I have not been able to find any information supporting that this is a steroid, and not suggested for long-term use so far. Can anyone chime in?