When RNA polymerase encounters a terminator sequence in the DNA, the process that stops is transcription.

Here's why:

* Transcription is the process of creating an RNA copy (mRNA) from a DNA template.

* Terminator sequences are specific DNA sequences that signal RNA polymerase to stop transcribing.

* Once the polymerase reaches a terminator, it detaches from the DNA, and the newly synthesized RNA molecule is released.

Therefore, the terminator sequence brings the transcription process to a halt.