貳

Traditionally analyzed as a phono-semantic compound, and also interpretable as a compound ideograph:

貝 (패) — semantic component, indicating value, accounting, tallying

弍 (이) — phonetic component supplying the sound (이), and semantically reinforcing “two”

Since 弍 itself is an old form of 二, the character can also be understood as “marking ‘two’ clearly in matters of value or accounting.”

이등 (貳等) — second class (classical usage)

이심 (貳心) — duplicity; double-mindedness

Modern usage:

Primary function today: formal numeral for 二.

Used in financial, legal, and administrative documents.

Prevents fraud or alteration (similar to 壹 for 一).

貳 means “two” and is used as the formal / financial variant of 二.

It is employed mainly in official documents, contracts, accounting, and legal texts to prevent alteration or forgery.

Because of this role, it is also called “the formal two”.

In classical usage, 貳 could also mean “secondary,” “subordinate,” and by extension “duplicity” or “betrayal” (literally, “having two minds”).

Related numerals (formal / financial):

壹 — one (formal)

貳 — two (formal)

參 — three (formal)

肆 — four (formal)

兩 — two (quantity, pair)

Among these, 貳 is the most widely known as the official and financial notation for ‘two.’