noun, noun which may take the genitive case particle 'no'
large size; large format
Describes paper, books, photographs, or other flat items that are larger than the standard size. Often used attributively with の.
I bought a large-format photo book.
I framed a large-format photograph and displayed it.
This book is large-sized and inconvenient to carry around.
ōban; large oval gold coin (Edo period)
Historical term for a large oval gold coin minted during the Edo period. Often contrasted with 小判 (koban), a smaller gold coin.
See also: 小判
An ōban from the Edo period is on display at the museum.
This map is printed in large format.
大判 is the larger of the two Edo-period gold coins (and the larger paper/photo format), while 小判 is the smaller coin (and can also mean a smaller format).
大判 describes a large-format item like a big book or paper, the opposite of a ポケットサイズ item made to fit in a pocket.
The coin name is shortened from 大判金, the large oval gold coin issued in early modern Japan. The general sense “large format” reflects the same formation 大判, “large-sized.”