sphere, globe, orb / (baseball) pitch / (slang, electronics) vacuum tube, valve

ball / bulb (as in a light bulb) / (slang, electronics) vacuum tube, valve / (baseball) pitch

spherical object / ball

technician, engineer

science and technology

technical

(computing) information technology (the practice of creating and/or studying computer systems and applications)

strengthens the prefixed adjective or adjectival noun

one who does the previous word's action: -ist, -er / (board games) counter for moves in shogi, go, etc.

hand / handicraft, skill, talent / one who does an action: -ist, -er / handwork