A vinaigrette is really a type of salad dressing. Vinaigrettes are based in oil and vinegar -- traditionally 3 parts oil to 1 part vinegar. Creamy dressings on the other hand, more often than not, refer to those that are made with a mayonnaise, sour cream, buttermilk or a yogurt base. Dressing and vinaigrette seem to be used interchangeably these days.