sunset

Etymology

From Middle English son-sett, Sonne set, equivalent to sun + set. In Gower's Confessio Amantis, before 1393.

noun

1. The moment each evening when the sun disappears below the western horizon.
   at sunset
   ’Twas sunset: when the sun will part There comes a sullenness of heart To him who still would look upon The glory of the summer sun. 1829, Edgar Allan Poe, “Tamerlane”, in Al Aaraaf, Tamerlane and Minor Poems
2. The changes in color of the sky before and after sunset.
3. (figurative) The final period of the life of a person or thing.
   'Tis the sunset of life gives me mystical lore. 1799, Thomas Campbell, Pleasure of Hope
   one's sunset years
4. (attributively) A set termination date.
   The tax increase legislation included a sunset clause requiring renewal to prevent the tax increase from expiring.
5. The region where the sun sets; the west.

verb

1. (business, politics, transitive) To phase out.
   We’ll be sunsetting version 1.9 of the software shortly after releasing version 2.0 next quarter.
   Last December, Yahoo announced plans to “sunset” more well-known services, including the pioneering social bookmarking service del.icio.us. 2011-04-19, Sumit Paul-Choudhury, “Digital legacy: The fate of your online soul”, in NewScientist