Chillers - that is, encompassing cold and not entirely warm purposes (3,6)
I believe the answer is:
Here is my best explanation:
'chillers' is the definition.
'encompassing cold and not entirely warm purposes' is the wordplay.
'encompassing cold' becomes 'ice' (I've seen this before. I am not sure about the 'encompassing' bit.**).
'and' means one lot of letters go next to another.
'not entirely' means to remove the last letter.
'warm' becomes 'hot' ('hot' can be a synonym of 'warm').
'purposes' becomes 'uses' ('use' can be a synonym of 'purpose').
'hot' with its last letter taken off is 'ho'.
'that is' acts as a link.