I used password instead of private key so it's more understandable for general population who have no idea about Bitcoin and cryptography.
you think the term "private key" is hard to understand because you know it is related to cryptography subject. but someone who has no knowledge of cryptography will read the word and interpret it literally:
a "private key" is a "key" that is "private" and keys open locks/secrets.
it is a very simple and descriptive term.