Fighters is a generic term for smalll attack ships
These ranged from one man fighter plane style ships to 4 man attack boats. They came in a bewildering variety of types, sizes and roles.
One example is space superiority fighter, a one man ship with heavy engines and a very accurate medium weight beam weapon, it was intended to shoot down enemy fighters and missiles.
Another was the anti-ship fighter, a big plane with 4 crew and a single heavy anti-ship missile.
Other types were ground attack or troop landing crafts.
Fighters as a class took heavy casualties during the war. Behind the scenes, it was quickly realized that the lives spent were not commesurate with the results obtained,
But the Fighters and their carriers were romantic favorites, and continued to garner funding and recruitment even though the ratio of their uses and successful missions fell continuously during the war.
After the Romulan war, fighter groups were considered economical units to station on planets for defense against raider and pirate attacks.