noun
x mark; cross mark
Used to indicate an incorrect answer, a negative choice, or something that is not allowed. Often contrasted with マル (circle) for correct/yes.
See also: 罰点
テストの答えにバツがついていた。
There was an x mark next to my answer on the test.
この書類の該当しない項目にはバツを付けてください
noun
Slang term for the drug MDMA (ecstasy). Used in informal contexts.
クラブでバツをやっている人を見かけた。
I saw someone doing ecstasy at the club.
Please put an x mark on the items that do not apply on this form.
罰点 is a more formal term for a cross mark indicating an error, often used in grading contexts.
From the shape of the letter 'x' or a cross mark. The slang sense for MDMA likely derives from the association of the letter 'x' with the drug ecstasy.