noun
number two; No. 2; second designated item
Used as a numbered label or designation. In everyday modern writing, Arabic-numeral 2号 is very common for this literal sense.
台風2号が沖縄に近づいている。
Typhoon No. 2 is approaching Okinawa.
二号車はホームの前の方に止まります。
Car No. 2 will stop toward the front of the platform.
noun
Old-fashioned and often disparaging euphemism for a kept mistress or concubine, implying a woman treated as 'No. 2' after the wife. Avoid as a neutral modern term.
彼には二号がいるという噂が立った。
A rumor spread that he had a mistress.
昔の小説では、彼女は有力者の二号として登場する
In the old novel, she appears as a powerful man's concubine.
The corresponding 'number one' label; 二号 is simply the next numbered designation in the literal sense.
Means 'second' in order or rank more generally, while 二号 is a label-style 'No. 2' using 号.
A more current word for a lover or mistress; 二号 sounds older, more euphemistic, and often derogatory.
An old word for a concubine or kept woman; like the figurative 二号, it is not a neutral modern term.
Written with 二 'two' and 号 'number; designation', literally 'number two.' The mistress sense is a figurative euphemistic extension from the idea of a secondary partner; the exact historical development is not specified.