
Luncheon
Time Specific
Luncheon refers to a meal served around midday and is more commonly used for special meals rather than daily lunch. 
Not Always Formal
While 'luncheon' sounds formal, it can be used for casual get-togethers as long as it's a planned meal. 
Cultural Usage
In some cultures, 'luncheon' may sound outdated; familiarity with modern usage is essential. 