Listened (8)
'listened' is the definition.
(attending is a kind of listening)
This is all the clue.
(Other definitions for attended that I've seen before include "'Went to, was present at (8)'" , "Was present at or waited upon" , "Paid heed" .)
'listened' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for heard that I've seen before include "Got to know (of)" , "Gave ear to" , "Perceived by the ear" , "Was told of" , "Detected aurally" .)
(Other definitions for tuned in that I've seen before include "Adjusted radio set" , "Prepared to hear" .)