guild (n.) Look up guild at Dictionary.com
early 13c., yilde (spelling later influenced by Old Norse gildi "guild, brotherhood"), a semantic fusion of Old English gegyld "guild" and gild, gyld "payment, tribute, compensation," from Proto-Germanic *gelth- "pay" (cognates: Old Frisian geld "money," Old Saxon geld "payment, sacrifice, reward," Old High German gelt "payment, tribute;" see yield (v.)).

The connecting sense is of a tribute or payment to join a protective or trade society. But some see the root in its alternative sense of "sacrifice," as if in worship, and see the word as meaning a combination for religious purposes, either Christian or pagan. The Anglo-Saxon guilds had a strong religious component; they were burial societies that paid for masses for the souls of deceased members as well as paying fines in cases of justified crime. The continental custom of guilds of merchants arrived after the Conquest, with incorporated societies of merchants in each town or city holding exclusive rights of doing business there. In many cases they became the governing body of a town (compare Guildhall, which came to be the London city hall). Trade guilds arose 14c., as craftsmen united to protect their common interest.