Based on size and shape:
* Boulder: A large, rounded, or irregularly shaped rock.
* Rock: A general term for any solid, naturally occurring mineral or petrified matter.
* Fragment: A piece of a larger rock that has been broken off.
* Clast: A fragment of rock, especially one that has been transported and deposited by a geological process.
* Irregularly shaped: This is a more descriptive term that can be used for any non-spherical rocky object.
Based on location:
* Asteroid: A rocky body orbiting the Sun, typically found in the asteroid belt between Mars and Jupiter. Many asteroids are irregularly shaped.
* Meteoroid: A small, rocky body in space. Meteoroids can be irregularly shaped.
* Meteorite: A meteoroid that has fallen to Earth. Meteorites can be irregularly shaped, but many are rounded by their passage through the atmosphere.
Other terms:
* Breccia: A rock composed of angular fragments of other rocks.
* Conglomerate: A rock composed of rounded fragments of other rocks.
Ultimately, the best term to use will depend on the specific context and the object's characteristics.