terminator

noun

1. Someone who terminates or ends something, especially (in later use) an assassin or exterminator.
2. A text character or string that serves to mark the end of a document or transmission.
3. The line between the day side and the night side of a moon, planet or other celestial body.

   “Harriot, looking at the moon, saw the irregular terminator, the highlights and shadows, the mountain ranges and valleys that Galileo had described – and he also convinced himself that he saw Galileo's imaginary crater.”

   “Another view captured by Wiseman shows the Earth divided by night and day. That frontier between light and darkness is known as the terminator.”

4. A DNA sequence that causes RNA transcription to cease and an mRNA transcript to break off.
5. An electrical device that absorbs reflection at the end of a transmission line.
6. An intelligent android created to destroy humans.

   “Opposite of natural monsters there are technological monsters such as terminators, cyborgs, and robocops—all of which undermine dichotomies between the artificial and the organic, the prosthetic and the natural.”