Reduce large tripod (5)
I believe the answer is:
easel
'tripod' is the definition.
(easel is a kind of tripod)
'reduce large' is the wordplay.
'reduce' becomes 'ease' (I've seen this before).
'large' becomes 'L' (eg in clothes sizes).
'ease'+'l'='EASEL'
(Other definitions for easel that I've seen before include "Blackboard supporter" , "Display tripod" , "Picture frame" , "Artistic tripod" , "Artist's prop" .)