There are many words that mean peace of mind. Such words include, but are not limited to contentment, serenity, and tranquility.
In Latin, the word 'mens" means mind.
It depends on where you live. In England, to give someone a "piece of your mind" means you're telling them off. Otherwise, in England and other English-speaking countries, to achieve "peace of mind" means, among other things, that nobody is telling you off, the bills are mostly paid and the police aren't banging on the door.
"What type of milk do you drink" is the question that comes to mind.
If out of mind means forgotten, the words could be abandoned or alone.
The word psyche is the Greek word meaning 'mind' or 'soul'
Portion?
one
Determined.
How about "peace of mind"? It's a compound word formed by combining "piece," "mind," and "classwork." It's like hitting three birds with one stone, but in a more peaceful way. So go ahead and use "peace of mind" to describe the serene state you achieve after completing your classwork.
"vision"
That is to visualize.
The root word psych- means mind. An example is psychology, which is the study of the mind.