rudiment

n. [ L. rudimentum, fr. rudis unwrought, ignorant, rude: cf. F. rudiment. See Rude. ] 1. That which is unformed or undeveloped; the principle which lies at the bottom of any development; an unfinished beginning. [ 1913 Webster ]

but I will bring thee where thou soon shalt quit
Those rudiments, and see before thine eyes
The monarchies of the earth. Milton. [ 1913 Webster ]

the single leaf is the rudiment of beauty in landscape. I. Taylor. [ 1913 Webster ]

2. Hence, an element or first principle of any art or science; a beginning of any knowledge; a first step. [ 1913 Webster ]

This boy is forest-born,
And hath been tutored in the rudiments
of many desperate studies. Shak. [ 1913 Webster ]

There he shall first lay down the rudiments
Of his great warfare. Milton. [ 1913 Webster ]

3. (Biol.) An imperfect organ or part, or one which is never developed. [ 1913 Webster ]