I've been wondering is it correct to say warrants are simply note format of options? Thank you!

Both terms are somewhat open-ended, but the classical warrant is a call option on a stock, issued in the form of a security by the underlying company itself. So it is an option, but unlike an exchange traded (or most OTC) option, it is not a side bet on the performance of the stock of a company between two unrelated parties. As a practical matter, the exercise of a warrant has a dilutive effect on the underlying stock, since it is generally fulfilled by the delivery of newly issued stocks by the company. Most of what is said about warrants also apply to (simple) convertible bonds.

In equity-linked derivs, i would agree with OP's statement: warrants are debt instruments (like notes) but they have an initial value similar to that of an OTC option. I will take premium from & post collateral to option purchaser if they do it with me OTC; my discount rate is linked to the cost of the collateral i have to postIf someone buys the same option from me in warrant format, I will take the premium but post no collateral - so my discount rate will be somewhere between OIS & my funding curve, depending upon what my treasury allows me to do with the money.

cool thank you both!I guess I am looking more from the trading perspective, so mutley's reply is what i was looking for