We present a topological interpretation of knot and braid contact homology in degree
zero, in terms of cords and skein relations. This interpretation allows us to extend
the knot invariant to embedded graphs and higher-dimensional knots. We
calculate the knot invariant for two-bridge knots and relate it to double
branched covers for general knots. In the appendix we show that the cord ring is
determined by the fundamental group and peripheral structure of a knot and give
applications.