To include (something) as a part.

“The design of his house incorporates a spiral staircase.”

To mix (something in) as an ingredient; to blend

“Incorporate air into the mixture.”

To admit as a member of a company

Being a type of company, a legal entity where the ownership has been arranged into shares. A shareholder has no responsibilities to the company and the potential losses of the shareholder are limited to the value of the stock turning to zero in the case of a bankruptcy.