括号
kuò hào · HSK 4
parentheses
括 = enclose + 号 = mark/symbol → enclosing marks
括 means to enclose or bundle together; 号 means a mark or symbol. Combined, 括号 literally reads as enclosing marks — the standard term for parentheses or brackets in writing.
号 — mouth 口 + tiger 虎
Originally written 號, combining 口 (mouth, indicating a cry or call) with 虎 (tiger) as the phonetic and a hint at a loud roar. It first meant to shout or call out, then extended to a name, title, or signal. The simplified form 号 keeps only the upper element.