1,000 at university consumed by cacophony - 'Up Mayo! (8)
I believe the answer is:
emulsion
'mayo' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's a link between them I don't understand?
'1000 at university consumed by cacophony 'up' is the wordplay.
'l000 at university' becomes 'lum' (I can't justify this - if you can you should give a lot more credence to this answer).
'consumed by' is an insertion indicator (inserted letters get consumed).
'cacophony' becomes 'noise' (synonyms).
''up' is a reversal indicator (in down clue: letters go upwards).
'lum' going inside 'noise' is 'noislume'.
'noislume' written backwards gives 'EMULSION'.
Can you help me to learn more?
(Other definitions for emulsion that I've seen before include "Type of paint" , "Wall paint" , "Mixture involving two liquids which do not readily combine" , "Mixture of insoluble liquids" .)