Caller/ˈkɔːlər/ Definition 1 of 4Pro Tip 1/3Telephone Etiquette When referring to 'caller' on the phone, politeness and clarity are important for respectful communication. Please hold while I transfer the call. Pro Tip 2/3Unknown Identity An 'unknown caller' may cause suspicion; it's wise to be cautious before sharing personal information. I didn't recognize the unknown caller's number. Pro Tip 3/3Not Just Voice The term 'caller' applies whether the person leaves a voice message or hangs up. The caller left a message after the beep.