Belly

Beli (ベリー Berī; represented by the belly sign: ) are the unit of monetary currency in One Piece, almost exclusively depicted in paper form, although coins do exist. Although closely resembling United States dollar bills, the large values on the notes harken to the Japanese yen.

It should be noted that because of the phonology, multiple english spellings exist; the most common among fans are is "Beli", although "Beri" is also used, "Berri" and "Belli" are used, but are somewhat uncommon. "Berry" for singular and "Berries" for plural is what is used by the 4kids dub and the VIZ manga. The author has spelled it both as "Berry" and "Belly" on the actual bills.

Nami's eyes tend to take the shape of the symbol of Belli when she hears that a large amount of money is involved. Especially when explaining that what she is doing has nothing to do with the money.