What is the difference between loss and lost?

When do we really use each one of them?

LOSE(v.)

It is a verb form and should be used as a verb in a sentence. Lost is its past tense and past participle.

example:

I lost my wallet.

"Lose some of your weight", mom told her son.

LOSS(n)

This is a noun form and can be used as a subject, object, or a complement.

example.

Loss of profit worries him no end.

During recession, businessmen incur substantial loss.

He was a great loss in the company.

LOOSE(adj.)

Loose is an adjective and is used to describe something.

example:

1. After a month's diet, his jeans became too loose for him .

2. His pet dog is on a loose. (break free)

The use of a Word is based upon its role in a sentence-how it is used in context.

These three are just some of the Words that are always used interchangeably without realising/knowing it.

The key is to identify the Words function in a sentence and then find out which Word fits the role.