A way of telling some one to calm down or to chill. Can also be used when something is personal and you want to say don't worry about it. Can be used to say you will relax.
You guys are making too much noise, you need to chill on it.
1) To mull over in one's mind indefinitely without taking any sort of action. It is normally applied to difficult situations, when the moral or correct choice is obscured or nonexistent.
A term used when a friend, family member, colleague or acquaintance is dealing with an issue (not known to the user of the term) that they themselves have the answer to or should deal with personally yet are unable to find/see such answer due to other factors bothering them (stress, anxiety, fear, fatigue etc) in their life.