Master is a term used to describe or address the dominant partner in a relationship or scene. Because it is an honorific of the dominant, it is common for "master" to be written with a capital letter.
The term "Master" can be used in a gender-independent way, but is mostly used only in reference to males. There is not otherwise a male equivalent. The female equivalent is Mistress or possibly Dominatrix.
Typically, Master is used to describe the dominant partner, or owner, in a Master/Slave relationship. It is sometimes, less commonly, used as a title for the Dominant in a D/s relationship. Not all Masters have equivalent skills, abilities, or orientations. For instance, a Master might have little specific expertise, while another may have great experience, long-standing interest, and considerable learned skills, both physical (e.g., skill with whips) and psychological (ability to 'get into' a submissive's head). To successfully maintain a Master/slave relationship, from the Dominant perspective, takes abilities and skills beyond or apart from normal relationship skills.
The Master has usually been given the right to exercise authority over the slave (or submissive) in some substantial sense, within a relationship that may extend to a full time, 24 hours a day, 7 days a week, or something less extensive (weekends as schedules permit, for instance). This is what is usually called power exchange in one variant or another. Although the Master will be understood to have a great deal of authority over the slave, this cannot extend to legal rights as such arrangements are not recognized in law anywhere in the developed world. Thus there must always be an implicit, if not explicit, element of consent involved, somewhat in imitation of legal contracts.
A Master might be a sadist but is unlikely to be a masochist, though sometimes a switch. The same is true, on the other side, of the slave/submissive, who may be a masochist but will not necessarily be; or the slave/submissive may be a switch.
Some people in a relationship, or just within a scene, enjoy the psychological impact of calling their dominant partner Master or having their submissive partner call them Master. Such usage is not by itself an indication that they are a Master any more than calling a partner 'honey' indicates that they are made of honey.
Many matchmaking web sites will encourage the usage of the term 'Master' for someone who is currently single and looking for a partner. Strictly speaking, this is an indication that the person is wanting to be a Master or slave owner (or in acting such a role) and is not an indication that they currently actually master anyone, or ever have.
This usage of the word Master -- as an honorific when neither party in a relationship consider themselves to be owned nor owner - is a common source of confusion when trying to use or understand BDSM terminology, given that the most accepted usage requires no certification or formal training. Most especially, a Dom might be called Master by his sub in a D/s relationship.
Head of Household
Not often used within the meaning of BDSM, but sometimes found in this context to mean someone who knows a lot about some subject, such as ropework or or computers or whips (as in "he is a famous whip master.")
Historically, a master craftsman (sometimes called only Master) was a member of a guild. In the European guild system, only master craftsmen were allowed to actually be members of the guild. An aspiring master would have to pass through the career chain from apprentice to journeyman before he could be elected to become a master craftsman. He would often have to produce a sum of money and a masterpiece before he could actually join the guild. Becoming a Master was often very hard.
The usage of Master in S&M parallels this usage in some ways, as early practitioners used to go through an 'apprentice' stage, often having to act as a submissive or masochistic as part of the process. However, Master in historical SM and Leather derived from 'Master/slave' rather than apprentice / journeyman / Master.
- Why Am I a Master? Author unknown
"To be completely woman you need a master, and in him a compass for your life. You need a man you can look up to and respect. If you dethrone him it's no wonder that you are discontented, and discontented women are not loved for long."