X mark; cross mark
Used to indicate an incorrect answer, disagreement, cancellation, or to mark something as wrong. Often contrasted with 丸印 (circle mark).
See also: 丸印
I put an X mark on the questions I got wrong on the test.
Please put an X mark on the unnecessary items in this document.
Compound of バツ (from the shape of the letter X, representing a cross or wrong mark) and 印 (mark, symbol).