A tick mattress, bed tick or tick is a large bag made of strong, stiff, tightly-woven material (ticking). This is then filled to make a mattress, with material such as straw, chaff, horsehair, coarse wool or down feathers, and less commonly, leaves, grass, reeds, bracken, or seaweed. The whole stuffed mattress may also, more loosely, be called a tick. The tick mattress may then be sewn through to hold the filling in place, or the unsecured filling could be shaken and smoothed as the beds were aired each morning. A straw-filled bed tick is called a paillasse, palliasse, or pallet, and these terms may also be used for bed ticks with other fillings. A tick filled with flock is called a flockbed. A feather-filled tick is called a featherbed, and a down-filled one a downbed; these can also be used above the sleeper, as a duvet.