Lineker accepts defeat describing list of technical terms (8)
I believe the answer is:
glossary
'list of technical terms' is the definition.
(I've seen this before)
'lineker accepts defeat' is the wordplay.
'lineker' becomes 'Gary' (footballer and broadcaster Gary Lineker).
'accepts' indicates putting letters inside.
'defeat' becomes 'loss' (I've seen this before).
'gary' enclosing 'loss' is 'GLOSSARY'.
'describing' is the link.
(Other definitions for glossary that I've seen before include "Explanatory list of terms" , "List of terms used in a particular subject" , "Specialised dictionary" , "one may see meaning here" , "List of technical terms in an appendix" .)