Short answer
A memecoin is a token whose value comes almost entirely from attention, community and jokes rather than revenue or a product. That makes the price extremely volatile.
Most memecoins start with a name, a picture and a ticker. There's usually no business behind them, no cash flow and no promise of anything. People buy because they expect other people to buy later, and sell when that attention moves on.
That doesn't make them all scams, but it does make them a game of momentum and timing. Prices can multiply in hours and fall 90% just as fast. Most new tokens never find a lasting audience at all.
If you trade them, size every position as money you can lose completely, check each token for rug pull warning signs, and read why most memecoins go to zero.
See the checks for yourself
18+ only. Self-custodial: you keep your keys. 0.5% per trade, no minimum. Memecoins can go to zero.