Theme or pattern (5)
I believe the answer is:
motif
This clue is a double definition.
'theme' is the first definition.
(I know that theme can be written as motif)
'pattern' is the second definition.
(motif is a kind of pattern)
(Other definitions for motif that I've seen before include "Recurrent theme as in musical work" , "Artistic theme, pattern" , "recurring idea" , "Repeated theme" , "Shape" .)