Networks and deposits
Confirmation
A block stacked above the one containing your transaction. The more there are, the less likely a reversal becomes.
A transaction included in a block can still disappear if that block is discarded in favour of a competing chain. Each block added on top makes that scenario exponentially less likely. The confirmation count required before releasing a payout is therefore a trade-off between safety and waiting.
The number only means something relative to block time. Two confirmations on Bitcoin, whose block takes ten minutes, is about twenty minutes. A hundred and twenty-eight confirmations on Polygon, whose block takes two seconds, is four minutes. A high count is not a sign of slowness.