The unique identifier of a transaction, typically the double SHA-256 hash of its serialized data.
The TXID is computed from the serialized transaction data. Malleability fixes (SegWit on BTC) reduce cases where IDs change. Users reference TXIDs to track confirmations in block explorers.
"After broadcasting, Bob shared the TXID so the merchant could monitor confirmations in a block explorer."
All terms and definitions may update as the Cryptionary improves.