*See also:*

**Appendix:Variations of "ao"**

## EnglishEdit

### EtymologyEdit

See the Wikipedia article ISO 216, the international standard on paper sizes.

### NounEdit

**A0** (*uncountable*)

- The base size in the series of the international standard, set such that it has an area of 1 square metre, where the ratio between the width and the length equals square root of 2, and the width of each size is equal to the length of next smaller size; dimensions: 1189 x 841 mm (1189.21 x 840.90 mm).