Sentence:  An end-compressing <WSD>monogon</WSD> for "F" is a <WSD>monogon</WSD> properly embedded in the complimentarySIC region "C" which is not homotopic (rel. boundary) into \partial C. 
Meaning of the word marked with <WSD> tags:  A two-dimensional object comprising one vertex, one edge both of whose ends are that vertex, and one face filling in the hollow formed by that edge.