Mattress \Mat"tress\, n. [OF. materas, F. matelas, LL. matratium; cf. Sp. & Pg. almadraque, Pr. almatrac; all from Ar. ma[.t]rah a place where anything is thrown, what is thrown under something, fr. [.t]araha to throw.]

1. A quilted bed; a bed stuffed with hair, moss, or other suitable material, and quilted or otherwise fastened. [Written also matress.]

2. (Hydraulic Engin.) A mass of interwoven brush, poles, etc., to protect a bank from being worn away by currents or waves.

Source: Webster's Revised Unabridged Dictionary (1913)