Source of Power for Phones, Remote Controls, Etc
Puzzle 19 of Things We Lose Piece of Cake Pack
Question is: Source of Power for Phones, Remote Controls, Etc
and the answer is: BATTERY
Word Meaning:
BATTERY — (electricity, electronics, countable) A device used to power electric devices, consisting of one or more electrically connected electrochemical cells or (archaically) electrostatic cells.
Definitions from Wiktionary.