mattress

UK: /ˈmætrəs/ US: /ˈmætrɪs/ ,(ma′tris)

WordReference Random House Learner's Dictionary of American English © 2025

mat•tress /ˈmætrɪs/   n. [countable]

1. a large pad used on a bed for support.

WordReference Random House Unabridged Dictionary of American English © 2025

mat•tress  (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. Building 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.

• Arabic maṭraḥ mat, cushion
• Italian materasso
• Old French
• Middle English materas 1250–1300

Collins Concise English Dictionary © HarperCollins Publishers::

mattress / ˈmætrɪs/ noun

1. a large flat pad with a strong cover, filled with straw, foam rubber, etc, and often incorporating coiled springs, used as a bed or as part of a bed
2. Also called: Dutch mattress a woven mat of brushwood, poles, etc, used to protect an embankment, dyke, etc, from scour
3. a concrete or steel raft or slab used as a foundation or footing

Etymology: 13th Century: via Old French from Italian materasso, from Arabic almatrah place where something is thrown