What is the best description for the word "collateral"?

Question

Quizplus · Accepted Answer

Collateral means "accompanying or existing in a subordinate, corroborative, or indirect relationship".
The missile hit its intended military target but there was also some collateral damage to the adjacent building.
"Something that occurs incidentally" is the best description for "side effect."
"The proof of the reality of something" is the best description for the word "manifestation."
"Having or affecting to sides" is the best description for the word "bilateral."

What Is the Best Description for the Word "Collateral