/rooh"deuh meuhnt/ , n.
1. Usually, rudiments .
a. the elements or first principles of a subject: the rudiments of grammar.
b. a mere beginning, first slight appearance, or undeveloped or imperfect form of something: the rudiments of a plan.
2. Biol. an organ or part incompletely developed in size or structure, as one in an embryonic stage, one arrested in growth, or one with no functional activity, as a vestige.
[ 1540-50; rudimentum early training, first experience, initial stage, equiv. to rudi ( s ) unformed, rough (see RUDE) + -mentum -MENT ( -i- for -i- after verbal derivs.) ]