also: はいりまち
noun
waiting for performers or celebrities to arrive
Slang used in fan culture, especially for waiting at stage doors or event venues to see idols, actors, or celebrities arrive. Often contrasted with 出待ち (waiting for them to leave).
See also: 出待ち
ファンが会場の入り口で入り待ちをしている。
Fans are waiting at the venue entrance for the performers to arrive.
入り待ちと出待ち、
I've done both waiting for them to arrive and waiting for them to leave.
出待ち means waiting for performers or celebrities to leave, while 入り待ち means waiting for them to arrive. Both are fan-culture slang.
Compound of 入り (いり, 'entering') + 待ち (まち, 'waiting'). The reading はいりまち uses the alternative reading はいり for 入り.