A 
-circuit is a k-chain
whose bounding (k-1)-chain vanishes.
k-Circuit
See also
k-ChainExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "k-Circuit." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/k-Circuit.html