Turn One on in the Dark
This page is the CodyCross answer for the clue below from Science Lab, Group 311, Puzzle 5 (Synthesis Reaction).
Question is: Turn One on in the Dark
and the answer is: LIGHTBULB
Word Meaning:
LIGHT BULB — An evacuated glass bulb containing a metal filament which is heated by electrical resistance to produce light.
Definitions from Wiktionary.