terminator
(ˈtɜːmɪneɪtə(r))
[a. late L. terminātor, agent-n. f. termināre to terminate.]
1. One who or that which terminates.
| 1846 Worcester, Terminator, he or that which terminates or bounds. 1890 Illustr. Lond. News 27 Dec. 810/2 The terminator of delights,..the desolator of abodes. |
2. Astron. The line of separation between the illuminated and unilluminated parts of the disk of the moon or a planet.
| 1770 Horsley in Phil. Trans. LX. 435 note, A great circle passing through the poles of the terminator. 1868 Lockyer Elem. Astron. iii. xvi. (1879) 92 The terminator—the name given to the boundary between the lit-up and shaded portions [of the Moon]. 1876 G. F. Chambers Astron. 69 Schröter found the terminator [of Venus] slightly concave. |
3. Biochem. A sequence of polynucleotides that causes transcription to end and results in the release of the newly synthesized nucleic acid from the template molecule. Freq. attrib.
| 1969 Biochemistry VIII. 4897/1 Would chains bearing such a chain-growth terminator be susceptible to the hydrolytic and pyrophosphorolytic reactions? 1977 World Bk. Sci. Ann. 1978 249 To get the gene to work..certain controlling base sequences had to be added at each end. One end had to have a ‘promoter’ sequence so transcription could start; the other end had to have a ‘terminator’ sequence to stop transcription. 1978 Nature 30 Mar. 398/1 Analysis of several ρ-independent terminators has revealed that in every case termination occurs distal to a GC-rich region within a run of uridine residues. |