Award ceremony insiders mass virtually in the end (4)
I believe the answer is:
emmy
'award' is the definition.
(I've seen this before)
'ceremony insiders mass virtually in the end' is the wordplay.
'ceremony insiders' becomes 'em' (I can't justify this - if you can you should give a lot more credence to this answer).
'mass' becomes 'm' (symbol used in Physics e.g. f=ma).
'in the end' indicates one should take the final letters.
The final letter of 'virtually' is 'y'.
'em'+'m'+'y'='EMMY'
Can you help me to learn more?
(Other definitions for emmy that I've seen before include "US TV award" , "TV's equivalent of an Oscar" , "Little girl" , "Television equivalent of Hollywood's Oscar" , "award in America" .)