A more thorough explanation:

A formal party is a type of party where guests are expected to dress in formal attire, such as a suit and tie for men and a formal dress for women. It is a social gathering that follows a strict dress code and often has a specific theme or purpose.

Examples of formal parties include weddings, galas, and black-tie events. At a wedding, guests are expected to dress formally to show respect for the couple and the occasion. A gala may have a specific theme, such as a masquerade ball, and guests are expected to dress accordingly. Black-tie events are typically fundraisers or charity events where guests are expected to dress in formal attire.

The examples illustrate the definition of a formal party by showing that it is a social gathering that requires guests to dress formally and follow a specific dress code. It is often associated with special occasions and events that require a certain level of formality and respect.