|to kill or destroy
|used as a suffix for a male name; circle
Taken from Wikipedia.org:
The kanji of Sesshou means to kill or destroy. Maru is usually a suffix that is often added at the end of a Japanese name for young males in samurai families. They would use this name until they were recognized as adults, whereupon they would adopt a new name.
However, it is said that maru can also translate as the word for circle, which is a common Japanese motif for what in the West is called the circle of life. Thus it is widely assumed that the name Sesshoumaru translates literally as destruction of the circle of life, or end of the circle of life. However maru also means perfect, so another possible translation is perfect destruction.
A fitting name for a youkai of his stature. Sesshoumaru is fully aware of his powerful status, and makes sure that others know that he is far superior to them in every way. He regards himself highly, addressing himself as kono Sesshoumaru, which translates to something like "I, Sesshoumaru." Known as "a demon among demons," his brutal reputation is feared throughout the lands, and enemies and commoners alike are wise to address Sesshoumaru with the proper -sama suffix.