マーク

マーク is a loanword from English "mark," used broadly for symbols, signs, logos, and indicators.

COMMON TYPES:

• ×マーク: X mark (wrong, prohibited)
• ○マーク: circle mark (correct, OK — unique to Japanese culture)
• チェックマーク: check mark
• 商標(しょうひょう)マーク: trademark symbol
• クエスチョンマーク: question mark

AS A SURU VERB:

マークする means to mark, to watch, or to keep an eye on:

• 警察(けいさつ)にマークされる: to be watched by the police
• 相手(あいて)のエースをマークする: to mark the opponent's ace (sports)

CULTURAL NOTE:
In Japan, ○ (circle) means correct/good and × means wrong/no. This is the opposite of some Western conventions where a check mark (✓) means correct.