from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A telescope equipped to measure small angular distances between celestial bodies.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An astronomical instrument, based on a telescope, for measuring the diameter of the sun; now used to measure the angular distance between stars and other celestial bodies.
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument devised originally for measuring the diameter of the sun; now employed for delicate measurements of the distance and relative direction of two stars too far apart to be easily measured in the field of view of an ordinary telescope.
from The Century Dictionary and Cyclopedia
- n. An astronomical instrument, consisting of a telescope having its objective sawed across in a plane passing through the optical axis, and each part arranged to move by sliding past the other, its exact position being shown by a micrometerscrew.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an instrument used to measure the angular separation of two stars that are too far apart to be included in the field of view of an ordinary telescope
helio-, from Ancient Greek Ἥλιος (Hēlios), from ἥλιος (hēlios, "sun") + meter, from French mètre, from Ancient Greek μέτρον (metron, "measure"). (Wiktionary)