With short selling, you "borrow" a security and sell it at the current price and then buy back the security at a lower price when it's time to return the securities you borrowed. With puts you're "buying the right" to sell a security at a set price and you pay a premium to secure that right, but you don't have to actually do it. So with a short your losses or returns are essentially uncapped but with a put your returns are capped at the price you agreed to minus the premium and your losses are just the premium you paid.

A short is based on borrowed stock, basically you borrow a bunch of shares from someone for and sell them for money, with a promise to return them later. If it goes down, that means when you rebuy it to return it's much cheaper and you can pocket the difference.

A put is a contract that you make with someone that says someone will buy a stock from you at a certain price if you decide to sell. The contract comes with an expiration date and a fee for you based off of calculated likelihood. The idea is, if the stock drops below that amount and then drops enough to cover the fee (the breakeven point), you invoke the contract and make a profit.

There is a lot more to it including reselling the contract etc. but frankly it's a glorified gambling hall for the most part unless you're in the know or have enough influence to move it yourself for specific tipping points.

Short selling = Borrowing shares and selling based on expecting a price drop, you can hold these as long as you like but you're going to be paying interest on borrowing them so you NEED to sell them eventually.

Put options instead give you the right to sell at a preset price within a specific time frame, so you could buy options at X price then even if it goes down later you are still guaranteed the price of the options.