| an imaginary sun moving uniformly in the celestial equator and taking the same time to make its annual circuit as the true sun does in the ecliptic. |
| mean sun n. A hypothetical sun defined as moving at a uniform rate along the celestial equator at the mean speed with which the real sun apparently moves along the ecliptic, used in computing the mean solar day. |
| mean sun
A hypothetical Sun defined as moving at a uniform rate along the celestial equator at the mean speed with which the real Sun apparently moves along the ecliptic, used in computing the mean solar day. |