Rudiment
/ˈɹuːdɪmənt/
noun
(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.”
(often in the plural) Something in an undeveloped form.
“I have the rudiments of an escape plan.”
A body part that no longer has a function
verb
To ground; to settle in first principles.