For convenience, people who are "In Charge" or causing sensation or whatever are referred to as Tops and the person on the other end is called a Bottom. Many people enjoy being both and are said to be switches.
Furthermore, Tops in a D/s context are called Doms (short for "dominants") and bottoms in D/s are subs (short for "submissive"). It's very important to remember that not all tops are doms, and not all bottoms are subs (i.e. not everyone into some parts of BDSM is into the D/s part.) The diagram should help make this clearer.
Likewise, Tops in a M/s context are called Masters and their bottoms are slaves. Although a lot of doms and subs enjoy using the terms "Master" or "slave", it should be realised that just as not all tops are Doms not all Doms are Masters, and just as not all bottoms are subs not all subs are slaves (i.e. not everyone into some parts of BDSM is into the M/s part.) The diagram should help make this clearer.
Not only are not all bottoms subs but a bottom is not necessarily submissive. At one end of the continuum is a submissive who enjoys taking orders from a dominant but does not receive any physical stimulation. At the other is a bottom who enjoys the intense physical and psychological stimulation but does not submit to the person delivering them; compare Topping from the bottom.
Fetish is included in the diagram on this page even though it isn't formally part of BDSM: fetishists find objects to be sexual arousing which are not normally associated with sex (whatever "normally" is supposed to mean); whereas BDSM is a group of activities or a relationship style. However, there is a very large overlap between the two communities and many BDSM people use fetish objects and clothing. Furthermore, many clubs allowing SM scenes have a strict dress code requiring some form of fetish clothes.
If you need to indicate gender, there are modified terms: maledom, femdom, Domme (which is a feminine form of gender neutral word Dom), malesub and femsub.