Final answer:
The party with the second largest number of members in the House of Representatives is referred to as the minority party.
Step-by-step explanation:
The name given to the party or coalition of parties with the second largest number of members in the House of Representatives is known as the minority party. When a single party does not hold a majority, parties may form a coalition to achieve a majority. In the U.S. Congress, there are two main parties, the Democrats and the Republicans, and they may elect leaders such as the majority or minority leader and the majority or minority whip within their respective party conferences or caucuses. The minority leader is the head of the party with the second largest number of seats.