Here's a breakdown:

* Giant stars: These stars are larger and more luminous than our sun, but smaller than supergiants. They are typically in the later stages of their life, having exhausted the hydrogen fuel in their core.

* Supergiant stars: These are the largest and most luminous stars, often with several times the mass and diameter of the sun. They are also in their later stages of life, burning their remaining fuel quickly and often ending in dramatic explosions called supernovae.

There are different classifications within these categories based on their temperature and luminosity, like red giants, blue giants, red supergiants, etc.