terminator
/ˈtɜːmɪneɪtə(r)/noun
1- a person or thing that terminates something终止者; 终止物。
1.1
- Astronomy the dividing line between the light and dark part of a planetary body【天文】（星体的）明暗界线。
1.2
- Biochemistry a sequence of polynucleotides that causes transcription to end and the newly synthesized nucleic acid to be released from the template molecule【生化】终止子。