Sentence:  Let "Ω" be a fixed, arbitrary, point. Then circles (in the classical sense) through "Ω" can be considered as lines. For convenience, such circles are called <WSD>clines</WSD> in this section. Two distinct <WSD>clines</WSD> cut in one point (ignoring "Ω" and the two cyclic points); it can happen that "Ω" is a double intersection point; in this case, one may say that the two <WSD>clines</WSD> are parallel, and that they meet at a point at infinity, which is "Ω". 
Meaning of the word marked with <WSD> tags:  A generalized circle.