What does pigeon grade mean?

Pigeon Grade, as used in firearms, specifically shotguns, is a term for a higher level of fit and finish - both mechanically and appearance wise for a limited number of guns. Pigeon grade guns are more valuable than regular production guns or Sporting guns. Recently some manufacturers have further subdivided into categories such as Silver Pigeon, Gold Pigeon, Onyx, etc. Pigeon grade guns will carry, often, more engraving, better wood (though there are again levels of wood, the best being "exhibition" wood), gold inlay, wood carving, etc. Some, at least a pre-war Winchester Model 12, will have an engraved pigeon near the serial number. Wood grade is not indicated by any markings, but by visualization. A greatly valuable combo would be an unfired pigeon grade gun with exhibition grade wood.