Gold signet rings are defined in the dictionary as rings which bear a sign. Depending on the nobility’s country of origin, they may typically set mens gold signet rings on the finger of the hand that their customs have prescribed over time.
However, some countries place their gold signet rings on the ring finger, specifically on the right hand such as the Swiss nobles. When used on a material such as a letter, they are likened to a signature which authenticates the document sent out.
The term can also be used to define any device used to make such impressions, similar to signet rings. Some cultures wear the signet rings differently to indicate their marital status such that nobles who use the ring with the seal facing inwards towards their palms are indicating that they are married while those who wear the ring facing up are not.
Signet rings are not limited to the nobles although most of the aspects of the term are attributed to them. To modern man, a signet ring can be a sign of membership or souvenir to a particular group much similar to a class ring.