What is the difference between a share and a stock?

They refer to the same thing.

You can say "How many shares do you have?" or "how many stocks do you have?"

share and a stock they are different thing,

When a Company runs, company want lots of money, the 50% of whole money invest the owner of company and 50% of money collect from public, then a company issue his share and public purchase the share of that company, then company get the money, instead of share the company pay the some money of profit with share holder.

Stock

The stock or capital stock of a business entity represents the original capital paid or invested into the business by its founders. It serves as a security for the creditors of a business since it cannot be withdrawn to the detriment of the creditors. Stock is distinct from the property and the assets of a business which may fluctuate in quantity and value.

They are essentially the same thing. A stock (certificate) represents a share in the business/corporation.

A share is a unit/piece of ownership in an organisation, fund, or company.

A stock market is a financial market in which shares are issued and traded, either through exchanges or over-the-counter markets.

no difference, they are the same