SPHERICAL TRIGONOMETRY • DICTIONARY ONE.COM • Definition of Spherical trigonometry

... had a rectilinear trigonometry and tables of chords. They had an approximate knowledge of parallax. [Footnote: Delambre, Hist. d'Astr. Anc., tom. 1, p. 184.] They could calculate eclipses of the moon, and use them for the correction of their lunar tables. They understood spherical trigonometry, and determined the motions of the sun and moon, involving an accurate definition of the year, and a method of predicting eclipses. They ascertained that the earth was a sphere, and reduced the phenomena of the heavenly bodies to uniform ...

— The Old Roman World • John Lord