Qual a diferença entre "stake", "stock" e "share"?

Good morning guys,

I´d like to know the difference between these words! The dictionary couldn´t really clarify them 100% to me.

See:

a. Stock:
the amount of money which a company has through selling shares to people
E.g.: They own 20% of the company's stock

b. Stake:
a share or a financial involvement in something such as a business
E.g.: He holds a 40% stake in/of the company.

c. Share:
one of the equal parts into which the ownership of a company is divided and which can be bought by members of the public
E.g.: He invests in stocks and shares.

Can I say: "He holds a 40% stock in the company"? or "He holds a 40% share of the company?"
Why on the example 'c' the example says "stocks and shares"? How do they differ exactly?

Can you see why I´m so confused?

Tks in advance.

Agnes