spotlight bulb; beam bulb
A bulb designed to produce a focused beam of light, typically used in interior lighting fixtures such as spotlights or track lighting.
I use beam bulbs in the living room downlights.
This beam bulb has a narrow beam angle, so it is suitable for illuminating specific spots.
Compound of ビーム (beam) and 球 (bulb/ball), a straightforward loanword-kanji combination for a specialized lighting component.