WordNet sense 1 (a city in east-central France on the Rhone River; a principal producer of silk and rayon):

Lyon

WordNet sense 2 (the council in 1274 that effected a temporary reunion of the Greek Orthodox with the Roman Catholic church):

Second Council of Lyons

WordNet sense 3 (the council of the Western Church in 1245 that excommunicated Holy Roman Emperor Frederick II and planned a new crusade against the Holy Land):

First Council of Lyons