Wordnet 3.0
NOUN (1)
1.
the angle subtended by the mean equatorial radius of the Earth at a distance of one astronomical unit;
The Collaborative International Dictionary of English v.0.48:
Solar parallax \Solar parallax\
The parallax of the sun, that is, the angle subtended at the
sun by the semidiameter of the earth. It is 8.80'', and is
the fundamental datum.
[Webster 1913 Suppl.]
WordNet (r) 3.0 (2006):
solar parallax
n 1: the angle subtended by the mean equatorial radius of the
Earth at a distance of one astronomical unit