An A for apprenticeship (8)
I believe the answer is:
articles
'apprenticeship' is the definition.
(I have seen 'Legal apprenticeship ' mean 'articles' so perhaps 'apprenticeship' could also mean 'articles')
'an a for' is the wordplay.
'an' becomes 'article' ('an' is an indefinite article in English).
'a for' becomes 's' (I can't explain this - if you can you should give a lot more credence to this answer).
'article'+'s'='ARTICLES'
Can you help me to learn more?
(Other definitions for articles that I've seen before include "Recitals (anag.)" , "Recitals about particular things" , "Legal apprenticeship" , "Things, objects" , "Items" .)