B or ,,a very small piece of material the inside of a lightbulb
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Explanation:
• a conducting wire or thread with a high melting point, forming part of an electric bulb or vacuum tube and heated or made incandescent by an electric current.
× (Electrical engineering: General) A filament is the thin wire inside a light bulb that emits light when heated by an electric current. The incandescent light bulb makes light by heating a metal filament wire to a high temperature until it glows.
° Word forms: filaments. countable noun. A filament is a very thin piece or thread of something, for example, the piece of wire inside a light bulb.
