A clear reply to "What is ethereum?" starts with two older coins that casino cashiers often list beside Bitcoin, Ethereum and Litecoin, which do very different jobs. Ethereum runs programs and carries tokens, while Litecoin mostly moves value from one address to another. Knowing how each network charges its fees and what its addresses look like keeps a transfer on the right chain, where a mistake may cost the whole amount. Nothing here is a reason to buy either coin.
Litecoin is one of the oldest coins, built on the Bitcoin design with changes that produce blocks about four times as often. On the question of Litecoin vs Bitcoin, Litecoin tends to confirm sooner and to charge lower fees, which is why some casinos accept it for deposits and withdrawals. It runs no smart contracts the way Ethereum does; its job is mainly payments. Its price swings like any unstable coin, so it suits moving value more than keeping it steady. A cashier usually states how many confirmations it needs.
An Ethereum wallet is an app or device that holds the keys to an account on the chain. The ETH and tokens stay recorded on the network itself; the wallet shows them and signs transfers. A new wallet displays its secret words once, and those belong on paper, kept apart from the phone. An ETH wallet address starts with 0x followed by forty hexadecimal characters. Several compatible chains use exactly the same format, so a 0x address alone does not reveal which network a transfer will travel on. The network name has to match on both sides.
Further questions
What does a Litecoin wallet address start with?
Litecoin addresses commonly start with L, M or ltc1, which tells them apart from Bitcoin addresses.
Which network should a Litecoin withdrawal use?
The native Litecoin network, not a copy of the coin issued on another chain; a coin sent to an address on another chain can be lost.
Does a failed Ethereum transaction still cost a fee?
Yes. A transaction that runs out of gas fails, and the gas it burned before failing is still paid.
Why does a wallet need ETH to send USDT on Ethereum?
Gas on Ethereum is paid in ETH even when the coin being sent is a token, so a wallet holding only USDT cannot move it.
What is Ethereum, and what is ETH?
Ethereum is a public blockchain that runs smart contracts and carries tokens; ETH, or ether, is its native coin and pays for every action on it.