Yeah, you would think that "call back" and "recall" would mean the same thing, right? :) But, no. :) So, "calling someone back" and "returning someone's call" mean the same thing. Person A calls person B. Person B misses the call, isn't there, gets a voicemail, whatever. Person B picks up the phone and "calls person A back", or person B picks up the phone and "returns person A's call". So far, so good. Now for "recall". If there's an issue with airbags in Honda cars, then you issue a recall. You're calling the cars back to the manufacturer to be fixed (calling them back to the nearest mechanic). You can send your sheepdog out and then you can whistle to call it back (to "recall" it). "Recall" also means "to call back to your mind a concept that was in your mind in the past", in other words "to remember". But "recall" doesn't mean to call someone back on the phone nor to return someone's call. And "redial" is yet another concept that doesn't mean any of the above. It means to dial again the exact same number you dialed a moment ago (or some time ago). Phones often have "REDIAL" buttons that do this automatically. Hope that helps! :)