Both Uses

parliament
in
War and Peace
(Auto-generated)

It naturally seemed to members of the English Parliament that the cause of the war was Napoleon's ambition;†
Chpt 9

parliament = legislative assembly that passes laws (existing in some countries)
With the present complex forms of political and social life in Europe can any event that is not prescribed, decreed, or ordered by monarchs, ministers, parliaments, or newspapers be imagined?†
Chpt 15 *

parliaments = legislative assemblies that pass laws (existing in some countries)

Definitions:

(1) (parliament with a lowercase "p")
a legislative assembly in certain countries (that can pass laws)
(2) (meaning too rare to warrant focus)
As a proper noun, you need to look at the context to determine the parliament to which Parliament is referring. For example, it could be the British Parliament, the European Union Parliament, the French Parliament, etc.