from
The Collaborative International Dictionary of English v.0.48
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.]
[1913 Webster]
1. A large pad stuffed with hair, moss, or other suitable
soft material, and quilted or otherwise fastened, used as
or in a bed, to support the human body while lying down.
[Written also {matress}.]
[1913 Webster]
2. (Hydraulic Engin.) A mass of interwoven brush, poles,
etc., to protect a bank from being worn away by currents
or waves.
[1913 Webster]
{innerspring mattress} A variety of mattress[1] having
springs inside to provide a flexible support; it is
considered more comfortable than a stuffed mattress.
[PJC]