a.u.

Fetched 2026-10-26 (cache).

Datamuse reports no synonyms or antonyms for this word.

Noun

1. {{abbreviation of|en|w:atomic units}}.
2. {{abbreviation of|en|w:arbitrary units}}.
3. {{abbreviation of|en|w:astronomical units}}.
4. {{abbreviation of|en|{{w|Absorbance#Absorbance of a material|absorbance units}}}}.

Source: Wiktionary · CC BY-SA 4.0 (Wiktionary dump) · cached copy, not a rewrite.