noun
shunned number
In computing, a number that is deliberately avoided or excluded, often in contexts like software versioning or network addressing.
このプロトコルでは、特定の回避番号が予約されている。
In this protocol, certain shunned numbers are reserved.
Compound of 回避 (かいひ, 'avoidance') and 番号 (ばんごう, 'number'). The exact origin as a technical term is uncertain.