- A3
-
a large size of paper about 16.5 inches or 420 millimetres wide and 11.5 inches or 297 millimetres longThesaurus: types and forms of paperhyponym
* * *
n. [mass noun] a standard European size of paper, 420 × 297 mm[as modifier]
A3 posters■ paper of this sizea prospectus printed on A3
Useful english dictionary. 2012.