Characters seen in flannelette or cotton garment? (7)
I believe the answer is:
doublet
'cotton garment?' is the definition.
(historical garment)
I cannot understand how the remainder of the clue works.
(Other definitions for doublet that I've seen before include "Old garment worn with hose" , "Historical jacket" , "Pairing" , "Part of old ensemble" , "Elizabethan man's jacket (worn with hose)" .)