is a specific kind of: ballplayer, baseball player | thrower.

is a broader term that covers: left-handed pitcher, left-hander, left hander, lefthander, lefty, southpaw | right-handed pitcher, right-hander | fireman, relief pitcher, reliever | screwballer | starting pitcher.

domain category: ball, baseball, baseball game | softball, softball game.

derivation: cast, hurl, hurtle | deliver, pitch | swirl, twiddle, twirl, whirl.