Determining the essential features of any sisal (8)
I believe the answer is:
analysis
'determining the essential features' is the definition.
I can't judge whether this defines the answer.
'of any sisal' is the wordplay.
'of' is an anagram indicator (the answer comes from or 'of' the letters).
'any'+'sisal'='anysisal'
'anysisal' anagrammed gives 'ANALYSIS'.
Can you help me to learn more?
(Other definitions for analysis that I've seen before include "Detailed examination of structure and content" , "Examination of structure of problem" , "Examination of structure (eg of psyche)" , "See 15" , "Detailed investigation" .)