the unit of ephemeris time, defined as a precise fraction of the length of the tropical year 1900.
noun, Astronomy. 1. time measured by the orbital movements of the earth, the moon, and the planets. noun 1. time that is based on the orbit of the earth around the sun rather than the axial rotation of the earth, one ephemeris second being 1/31 556 925.9747 of the tropical year 1900. It was used […]
[ih-fem-uh-ron, -er-uh n] /ɪˈfɛm əˌrɒn, -ər ən/ noun, plural ephemera [ih-fem-er-uh] /ɪˈfɛm ər ə/ (Show IPA), ephemerons. 1. anything short-lived or ephemeral. 2. ephemera, items designed to be useful or important for only a short time, especially pamphlets, notices, tickets, etc. /ɪˈfɛməˌrɒn/ noun (pl) -era (-ərə), -erons 1. (usually pl) something transitory or short-lived n. […]
[ih-fem-uh-rop-ter-uh n] /ɪˌfɛm əˈrɒp tər ən/ adjective 1. belonging or pertaining to the insect order Ephemeroptera, comprising the mayflies. noun 2. . /iːˌfɛməˈrɒptərən/ noun 1. another word for ephemerid adjective 2. of or relating to the Ephemeroptera
[ih-fem-er-uh s] /ɪˈfɛm ər əs/ adjective 1. .