Miter saws are designed for making precise crosscuts at any angle from 0 to 45 degrees. They're very versatile and highly portable, able to travel from the shop to job locations and back with ease. There are two types of miter saws: the compound miter saw and the Sliding compound miter saw. Each has the ability to make angled crosscuts, but there are also some features that are particular to each.
Compound miter saws have motors that can swing left and right and tilt for beveled cuts. They're useful for cutting picture frames or any other project that requires making angled cuts in two place
Sliding Compound miter saws are much more versatile than either of the above. They're capable of making much longer cuts thanks to a sliding head.