Wiktionary
lower house
n. One of the two parts of a parliament in some countries.
Wikipedia
Lower house
A lower house is one of two chambers of a bicameral legislature, the other chamber being the upper house.
Despite its official position "below" the upper house, in many legislatures worldwide, the lower house has come to wield more power.
A legislature composed of only one house is described as unicameral.
Usage examples of "lower house".
Martez leads a faction in the Lower House that fought each new expenditure.
Or if the Conservative Social Democrats had won two more seats in the lower house while the Liberal Royalists had gained a critical appointment in the Bureau of Education?