/ma"tris/ , n.
1. a large pad for supporting the reclining body, used as or on a bed, consisting of a quilted or similarly fastened case, usually of heavy cloth, that contains hair, straw, cotton, foam rubber, etc., or a framework of metal springs.
2. See air mattress .
3. a mat woven of brush, poles, or similar material, used to prevent erosion of the surface of dikes, jetties, embankments, dams, etc.
4. a layer of concrete placed on bare ground, as to provide a footing; mat.
5. a layer of any material used to cushion, protect, reinforce, or the like.
[ 1250-1300; ME materas materasso matrah mat, cushion ]