properly, cælo-, combining form of L. cælum, long spelt cœlum sky, heavens, as in Cœlometer [see -METER], see quot. Cœlonavigation, a term proposed for navigation by observation of the heavens (opp. to geo-navigation).
1883. Fisheries Exhib. Catal., 30. Cœlometer for illustrating nautical Astronomy.
