Rudiments

noun

1. (often in the plural) A fundamental principle or skill, especially in a field of learning.

   "We'll be learning the rudiments of thermodynamics next week."

2. (often in the plural) Something in an undeveloped form.

   "I have the rudiments of an escape plan."

3. A body part that no longer has a function
4. In percussion, one of a selection of basic drum patterns learned as an exercise.