D/s and M/s Relationships: How They Differ
A common question that comes up a lot when discussing power exchange is the difference between the terms D/s and M/s (or O/p). In many kink spaces M/s dynamics are completely absent, disconnected from the space or kept as some kind of extreme fantasy. As a result, while almost everyone understands a D/s dynamic, many don't even know what the M/s acronym stands for. So to start, let's define D/s and M/s.
D/s or Dominant/submissive dynamics are built around short term exchange of power and high intensity play during scenes. A D/s dynamic may keep the trappings of the dynamic outside of scenes and even maintain the full exchange of power, but play is entirely kept within scenes.
M/s or {Master | Mistress}/{slave | submissive} dynamics (also known as O/p or Owner/{property | pet} in many modern circles), by contrast, are historically defined as subset of D/s dynamics which maintain a 24/7 total exchanges of power. M/s dynamics are generally low intensity, blending the line between in and out of scene, or ignores it entirely. While they may include periods of intense scene play, these are not core to the dynamic and the dynamic should be able to function without them. As a result of the 24/7 exchange of power, M/s dynamics tend to have higher baselines for formal protocol.
While it's possible for M/s dynamics to have elements of D/s dynamics and vice versa, it's much more common for M/s dynamics to borrow from D/s dynamics than the other way around. M/s dynamics tend to be highly structured and negotiated dynamics, as opposed to D/s dynamics, where negotiation is often short and focused more on consent than structure. Due to blending of definitions, water has become extremely muddied in modern times with much debate on definitions with many conflicting ideas.
Quick final aside: M/s is a fairly old fashioned term, and many now prefer the term O/p due to the connotations of slavery, especially as it appeared in slave trade from the 14th century onwards (and a rather misguided attempt to unmuddy the water by introducing a new term, see relevant XKCD). It's our belief that the imagery of this form of slavery is poorly suited to how the term M/s uses the meaning of slavery. Instead the imagery of a Roman household slave is a much better mental image, where the slave is a valued and respected member of the household, rather than treated as a subhuman object (that said if your into that, good for you, no judgement).