Dinner, banquet, feast are comparable when denoting an elaborate meal that is served to guests or to a group (as of members of a club or association) and that often marks some special occasion (as an anniversary) or honors a particular person.
Dinner which basically means the chief meal of the day is the most general of these terms; it is appropriately used of any elaborate and formal meal served to guests or to a group and is the preferred term for use in invitations and in colorless reference to such an affair.
Typically, banquet suggests the sumptuousness of the meal, the magnificence of its setting, and often the ceremonial character of the occasion and entertainment.
It may stress the excellence and elaborateness of food and service or especially in popular use it may imply no more than a formal dinner held elsewhere than in a private home.
Feast is often interchangeable with banquet but it may carry over a feeling of its other meaning of a festival of rejoicing and then stresses the shared enjoyment and pleasure in the occasion that gives rise to the meal.
Unlike the other terms of this group feast has frequent extended use with the notion of a source of, often shared, enjoyment.