What does the clock symbol next to the battery indicator on my iPhone mean?

I had this clock on one of our phones for several years and couldn't figure out why it was there. I had no alarms set, not on the phone clock nor on any apps or programs. I eventually would give up exhausting all efforts to find this elusive alarm and rid myself of the icon. Today I solved the riddle! I set an alarm on the normal phone clock, then deleted it and the icon disappeared! I hope this response helps someone.