noun, noun which may take the genitive case particle 'no'
double; twice as much; twofold
Indicates a quantity, size, or degree that is two times the original. Used as a noun or with の to modify another noun.
今年の売り上げは去年の二倍になった。
This year's sales were double last year's.
この箱はあの箱の二倍の大きさです。
This box is twice as big as that one.
二倍 explicitly spells out 'two times' by attaching the number, while 倍 alone can already stand for 'double' as a bare noun.
一倍 now usually means the same amount (×1), while 二倍 means double (×2), even though 一倍 historically also meant 'double', causing confusion.
二倍 is a noun meaning 'twice the amount' as a static quantity, whereas 倍増 describes the process or event of doubling.
Standard kanji spelling.
Common in informal writing, advertisements, or when numerals are preferred.
Compound of 二 (two) and 倍 (times, -fold).