[UNDER-1 5 b.] A lower layer; a substratum.
1896. Daily News, 15 Dec., 2/2. The carpets are of heavy velvet pile on an underlayer of elastic felt and cork.
1904. W. P. Ker, Dark Ages, 198. Rodulphus represents the permanent underlayer of medieval absurdity above which Gerbert rises so eminently.
