time zone

Concise Oxford English Dictionary © 2008 Oxford University Press:
zone/zəʊn/

▶noun

• 1 an area distinguished on the basis of a particular characteristic, use, restriction, etc.

  ■ (also time zone) a range of longitudes where a common standard time is used.

• 2 chiefly Botany & Zoology an encircling band or stripe of distinctive colour, texture, etc.

• 3 archaic a belt or girdle.

▶verb

• 1 divide into or assign to zones.

• 2 archaic encircle as or with a band or stripe.

• 3 (zone out) N. Amer. informal fall asleep or lose concentration.

– derivatives
zonal adjective,
zonally adverb.

– origin ME: from Fr., or from L. zona ‘girdle’, from Gk zōnē.