Source : Webster's Revised Unabridged Dictionary (1913)

Attender \At*tend"er\, n.
   One who, or that which, attends.

Source : WordNet®

attender
     n 1: someone who listens attentively [syn: {hearer}, {listener},
          {auditor}]
     2: someone who waits on or tends to or attends to the needs of
        another [syn: {attendant}, {tender}]
     3: a person who participates in a meeting; "he was a regular
        attender at department meetings"; "the gathering satisfied
        both organizers and attendees" [syn: {attendant}, {attendee},
         {meeter}]