blue + green.
Compare with the color called orange in Modern English, which was called geoluhread (“yellow-red”) in Old English and Middle English.
blue-green (comparative more blue-green, superlative most blue-green)
- Of a color between blue and green; darker shades are called teal, lighter ones are cyan.
Derived terms 
color between blue and green
- ^ Kenner, T.A. (2006). Symbols and their hidden meanings. New York: Thunders Mouth. p. 11. ISBN 1560259493.