Memory of online concert (5)
I believe the answer is:
eprom
'memory' is the definition.
(short for erasable programmable read-only memory)
'online concert' is the wordplay.
'online' becomes 'e' (abbreviation for electronic, e.g. in ecommerce).
'concert' becomes 'prom' (abbreviation for promenade concert).
'e'+'prom'='EPROM'
'of' is the link.
(Other definitions for eprom that I've seen before include "Memory" , "chip" .)