First off, no security is more derivative than a share of stock, which is not really ownership of a company (though it's usually claimed so) but merely a right to whatever cash management deigns to share, plus a right to whatever is left over in a bankruptcy, plus a right to participate in corporate governance in whatever limited ways a company's bylaws permit.
Investopedia explains Stock
A holder of stock (a shareholder) has a claim to a part of the corporation's assets and earnings. In other words, a shareholder is an owner of a company. Ownership is determined by the number of shares a person owns relative to the number of outstanding shares. For example, if a company has 1,000 shares of stock outstanding and one person owns 100 shares, that person would own and have claim to 10% of the company's assets.
Investopedia explains Equity Derivative
Investors can use equity derivatives to hedge the risk associated with taking a position in stock by setting limits to the losses incurred by either a short or long position in a company's shares. The investor receives this insurance by paying the cost of the derivative contract, which is referred to as a premium. If an investor purchases a stock, he or she can protect against a loss in share value by purchasing a put option. On the other hand, if the investor has shorted shares, he or she can hedge against a gain in share price by purchasing a call option
What Does Underlying Security Mean?
The security on which a derivative derives its value. For example, a call option on Google stock gives the holder the right, but not the obligation, to purchase Google stock at the price specified in the option contract. In this case, Google stock is the underlying security