1. adjective /ˈkɒmp(ə)ɹəb̩l,kɒmˈpæɹəb̩l,kəmˈpɛɹəbl̩/
a) Able to be compared (to).
An elephant is comparable in size to a double-decker bus.
b) Similar (to); like.
You cant say that robbing a bank is like pickpocketing. The two are just not comparable.
2. noun /ˈkɒmp(ə)ɹəb̩l,kɒmˈpæɹəb̩l,kəmˈpɛɹəbl̩/
Something suitable for comparison
Wikipedia foundation.