Three students welcoming university break (4)
I believe the answer is:
lull
'break' is the definition.
(I know that lull is a type of break)
'three students welcoming university' is the wordplay.
'three students' means three replacements for 'student'.
'student' becomes 'l' (as in L-plates for learner drivers).
'student' becomes 'l' (as in L-plates for learner drivers).
'student' becomes 'l' (as in L-plates for learner drivers).
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'university' becomes 'u' (abbreviation for university).
'l'+'l'+'l'='lll'
'lll' going around 'u' is 'LULL'.
(Other definitions for lull that I've seen before include "Rock to sleep" , "Short period of quiet" , "Calm - calm by deception" , "Short period of calm" , "A quiet spell as in a storm" .)