Webster's Online Dictionary
with Multilingual Thesaurus Translation

 
Earth's largest dictionary with more than 1226 modern languages and Eve!

Specialty Expressions: ASTRONOMICAL DAY

ExpressionsDomainDefinition
Astronomical dayAerospaceA mean solar day beginning at mean noon, 12 hours later than the beginning of the civil day of the same date. Astronomers now generally use the civil day. See Julian day, astronomical time. (references)

Source: compiled by the editor from various references; see credits.

Top