Definition - What does Collared mean?
Collaring represents the act of submitting oneself to the dominant. Often regarded as a powerful symbol in the world of BDSM, a collared individual publicly represents the D/s relationship between the two parties. Some people choose to have a formal collaring ceremony that is not unlike a traditional marriage ceremony. In fact, to most people who participate, a bondage collar is regarded as being synonymous to a wedding ring. It usually shows that the submissive in question is off-limit to other dominants.
In a more casual context, the act of being collared can also be used in light bondage or role playing.
Kinkly explains Collared
There are several types of collars that can be used, but they do not necessarily represent a permanent D/s relationship. The collar of protection, for example, is a symbol to show that a submissive without a permanent Dominant is under the protection and watch of a Dominant that he or she knows. They may or may not engage in play sessions together. This form of collaring is normally applied to individuals who have suffered some form of trauma and consequently need to feel safe.
A training collar often occurs after several discussions about the needs, desires, conditions, dislikes, likes, soft and hard limits, and the rules established by both parties.
A permanent collar represents the fact that the submissive and the Dominant have reached a fully-established relationship which they hope will last for life.