In JoJo's Bizarre Adventure, each Stand has a 'range' attribute limiting the distance at which they can manifest. In 7th Stand User, each Stand and many attack moves also have individual ranges:
Short-range (S) attacks have the highest power output, but do little damage to enemies that are far away.
Mid-range (M) attacks have a reliable damage output regardless of range.
Long-range (L) attacks have the lowest power output, but can hit enemies at any range.
For example, attacking an enemy at long range with a short-range attack will do nearly no damage at all. Attacking an enemy at short range with a long-range attack will damage them, but will consume much more SP and won't do nearly as much damage as a short-range attack on the same enemy.