Laundry Tool, Musical Instrument, and Shredded Abs

This page is the CodyCross answer for the clue below from Physics, Group 1897, Puzzle 4 (Wave Function).

Question is: Laundry Tool, Musical Instrument, and Shredded Abs

and the answer is: WASHBOARD

Word Meaning:

WASHBOARD — A board with a corrugated surface against which laundry may be rubbed.

Definitions from Wiktionary.