The BDSM Collar

How do you define it, and what does it mean to you?

Joining - Giving - Submission - Devotion - Ownership - Pride - Love - Understanding - Accepting - Belonging
It is the Master's mark of ownership. It is the slave's showing of trust in her Master, honour of having been taken by her Master, and pleasure in being known as His slave/sub.
It depends totally on the people involved. For short-term use, some use it as an "i belong to ____" for the evening. Some use a collar only as a lifetime commitment. The collar in this subculture is as sacrosanct as the wedding ring in the general culture. An outward symbol of an inner decision.
To me the collar is a play toy that says, "We are suspending our vanilla lives and are into our Dom/sub roles." It means we are free to play out our fantasies and desires.
Since I have no collared submissives or slaves, a collar means, to me: Look but don't touch. Ask, negotiate, and be polite. Accept any service offered with warm thanks to them, and if appropriate, pass kind compliments on to the Master or Mistress of the collared submissive.
Devotion to serving the one who owns the collar. Obedience. Respect, and making the Dominant proud to have chosen you as a submissive. Striving in all ways to please Her and to make Her life easier.
A collar, much like a wedding ring, is a physical symbol of the relationship between a Dominant and a submissive.
The relationship exists even when the collar isn't being worn, but like the ring, when the collar is being worn it is a signal that this person is connected with another person. It represents the vows to each other made by the Dom and sub.
There are several collars, as far as I am aware:
1. Play Collar: usually just for the night
2. Consideration Collar: similar to the play collar, with the possibility of advancing to a training contract.
3. Training Collar: comes with a contract and has associated duties and activities to increase value as a submissive.
5. Formal Collar: long-term commitment.
There are many definitions and connotations, depending on the situation. For a committed D/s couple, it is a symbol. For the unknowing, it can be a fashion statement. To the submissive, it can be an absolutely thrilling symbol of their submission. To the Dom, it can be an intense symbol of their domination.
Personally, I love the feeling of my collar. It reminds me constantly when I am wearing it that I am under the control of the person who placed it around my throat.
A device to which you voluntarily agree to, which - if tightened too much - may result in singing falsetto. It generally means I'll do exactly what Her Devine Shadow says!
Control and commitment. It's a promise to obey (from the submissive), and to protect and cherish (from the dominant). It can also be used for those who want to be a pet.
Some people wear a collar without being committed to anyone, just as a way of saying "I'm kinky."