A point at which the end of one strand meets the end of another. If a knot has one incoming strand and one outgoing strand, it is a serial knot. If it has one incoming strand and two outgoing strands, it is a spawn knot. If it has multiple incoming strands and one outgoing strand, it is a sync knot. A Cilk program does not produce serial knots or knots with both multiple incoming and multiple outgoing strands.