'To calculate one's nativity' definitions:

Definition of 'To calculate one's nativity'

From: GCIDE

Nativity \Na*tiv"i*ty\, n.; pl. Nativies. [F. nativit['e], L. nativitas. See Native, and cf. {Na["i]vet['e]}.]
1. The coming into life or into the world; birth; also, the circumstances attending birth, as time, place, manner, etc. --Chaucer. [1913 Webster]
I have served him from the hour of my nativity. --Shak. [1913 Webster]
Thou hast left . . . the land of thy nativity. --Ruth ii. 11. [1913 Webster]
These in their dark nativity the deep Shall yield us, pregnant with infernal flame. --Milton. [1913 Webster]
2. (Fine Arts) (capitalized) A picture representing or symbolizing the early infancy of Christ. The simplest form is the babe in a rude cradle, and the heads of an ox and an ass to express the stable in which he was born. [1913 Webster]
3. (Astrol.) A representation of the positions of the heavenly bodies as the moment of one's birth, supposed to indicate one's future destinies; a horoscope. [1913 Webster]
The Nativity, the birth or birthday of Christ; Christmas day.
To cast one's nativity or To calculate one's nativity (Astrol.), to find out and represent the position of the heavenly bodies at the time of one's birth. [1913 Webster]