Tangle

The Tangle is the directed acyclic graph ledger used by the IOTA network, in which every new transaction validates two earlier transactions instead of being packed into a block by a miner or validator. Because users confirm each other's transactions, the design was intended to work without mining fees and to scale as usage grows. Confirmation is probabilistic: a transaction becomes harder to reverse as more later transactions reference it, directly or indirectly. That means confirmed is a matter of accumulated weight rather than a fixed number of blocks, so wallets may display different confidence levels for the same payment. The Tangle is the best-known DAG ledger, and its name is often used as shorthand for feeless, blockless designs in general.