Unicameralism
governmental practice of having a single legislative or parliamentary chamber
In government, unicameralism is when there is only one legislative or parliamentary chamber. Therefore, a unicameral legislature or unicameral parliament is a legislature with one chamber. It comes from the Latin "uni" (meaning one) and "camera" (meaning chamber).
Unicameral legislatures are used around the world.
Since 1937, the US State of Nebraska’s Nebraska Legislature has been unicameral, however all other US states use a bicameral system.