A call received when the recipient was unavailable (missed call); commonly shown on mobile phones as a missed-call notification.
朝、携帯を確認したら不在着信が3件入っていた。
In the morning when I checked my phone, there were three missed calls.
打ち合わせ中で出られず、不在着信に気づかなかった。
I was in a meeting and couldn't answer, so I didn't notice the missed call.
不在着信に折り返し電話をして、要件を確認した。
I called back the missed call and confirmed the matter.