Capital (noun): the assets, goods, possessions or money which forms the corpus of something which yields income. "The unit trust is a good capital investment with a total yield of 5% on the capital employed."

equity: "The company's unrestricted equity is £50,000,000."
principal: "Interest on a loan must be repaid before repayment of the principal."

Antonym: liabilities: "If a company's liabilities are greater than its capital, the company may have no choice but to enter into insolvent liquidation."

Other form of the word - capitalization: "The current capitalization of the company is set forth in the income statement."
Common phrases: share capital of a company; capital investment; capital asset

Note: For many people, capital represents savings. In the company law context, capital means the amount paid for shares, i.e. the share capital is 50 shares at GBP 5 each, thus the company’s share capital is GBP 250.
Source: Your Dictionary