Answer: a monomial has one term, binomial has 2 terms, and trinomial has 3.
Explanation:
using a bit of greek and latin roots, we can observe that all 3 terms have the same suffix of nomial in them. From this, we know that mono means one, bino means two, and tri means 3. Fun fact, there's also polynomial (if you did or didn't know), which is multiple terms more than 3.