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.