interlocking

/IH1 N T ER0 L AA0 K IH0 NG/
verb
  1. 1

    To fit or clasp together securely.

  2. 2

    To interlace.

noun
  1. 1

    An arrangement of signal apparatus that prevents conflicting movements through a set of tracks such as junctions or crossings.

Source: https://en.wiktionary.org/wiki/interlock, https://en.wiktionary.org/wiki/interlocking