MICHEL: Your mother called. The auction people dropped the lamp that we bought at her place and dropped hers off here and she’s desperate to have it for some soiree at her house this evening.
A soirée is a sophisticated evening party, often with some kind of cultural or musical focal point, such as a classical music performer, or an intellectual discussion. It dates back to the 18th century in France and England, when wealthy, well-married ladies would invite accomplished guests to their home for refreshments in the evening. The word is simply the French word for “evening”.
The Annotated Gilmore Girls 