Confirmation
A new block added after the block that contains your transaction; more confirmations mean more finality.
A transaction gets its first confirmation when it is included in a block. Each block added after that counts as one more confirmation. The more confirmations a transaction has, the harder it is to reverse, so services wait for a certain number before crediting a deposit.
How long that takes depends on the chain. Bitcoin blocks come about every 10 minutes, Litecoin every 2.5 minutes, Monero about every two minutes, and chains like Solana, TRON or Stellar settle within seconds. Monero also locks received funds for 10 blocks before they can be spent.
For swaps, confirmations explain most of the waiting time. Your deposit is not processed until it has enough confirmations, and a low network fee can delay the first one considerably on busy chains. You can follow the count in a block explorer using your transaction hash.
