Simplify the following text for a Grade 7 native English-speaking person.
Original: The House of Lords ( commonly referred to as `` the Lords '' , officially referred to as `` the Lords Spiritual and Temporal '' in Acts of Parliament , and also known as House of Peers for ceremonial purposes ) is the upper house of the Parliament of the United Kingdom , the United Kingdom 's national legislature .
Simplified: The House of Lords is one of the two Houses of Parliament of the United Kingdom ( UK ) .