Novel artist in adopting old pattern of lines (9)
I believe the answer is:
striation
'pattern of lines' is the definition.
'striation' can be an answer for 'pattern' (striation is a kind of pattern). I am not certain of the 'of lines' bit.
'novel artist in adopting old' is the wordplay.
'novel' indicates anagramming the letters (letters in a new or novel order).
'adopting' indicates putting letters inside (inserted letters are taken on or adopted).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'in' placed around 'o' is 'ion'.
'artist' with letters rearranged gives 'striat'.
'striat'+'ion'='STRIATION'
Can you help me to learn more?
(Other definitions for striation that I've seen before include "Marking with streaks" , "A marking of parallel lines" .)