sunset

noun

1. (countable, uncountable)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.”

2. (countable, uncountable)The changes in color of the sky before and after sunset.
3. (countable, figuratively, uncountable)The final period of the life of a person or thing.

   “one's sunset years”

   “'Tis the sunset of life gives me mystical lore.”

4. (attributive, countable, uncountable)A set termination date.

   “The tax increase legislation included a sunset clause requiring renewal to prevent the tax increase from expiring.”

5. (countable, uncountable)The region where the sun sets; the west.

verb

1. (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.”

   “Here’s what you need to know about Amazon’s decision to sunset its older e-readers and tablets, and what that means for you.”