Bi-

Origin

From Latin bis ("twice").

Prefix

1. two
2. (chemistry, proscribed) half

Usage notes

In an old, common method used to indicate the presence of an acidic hydrogen, sodium hydrogen sulfate is called sodium bisulfate and sodium hydrogen carbonate is called sodium bicarbonate. This method is not recommended by IUPAC and does not denote a “doubling up” of a specific group, which is reserved for the Greek prefix di-, as in

2

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Synonyms

• di-
• duo-

Derived terms