Lots of celebrations outside Japanese school (6)
I believe the answer is:
dozens
'lots' is the definition.
('dozens' can be a synonym of 'lots')
'celebrations outside japanese school' is the wordplay.
'celebrations' becomes 'dos' (a do is a party or celebration).
'outside' indicates putting letters inside.
'japanese school' becomes 'zen' (Japanese school of Buddhism).
'dos' going around 'zen' is 'DOZENS'.
'of' is the link.
(Other definitions for dozens that I've seen before include "Sets of twelve" , "Large numbers" .)