A dedicated device that stores private keys in isolation and signs transactions internally, so the key never reaches an internet-connected computer.
Why it matters
A hardware wallet protects the key. It does not judge whether a transaction is a good idea — it displays the request and asks. In the Ledger Connect Kit compromise and the Radiant Capital breach, devices behaved exactly as designed while funds were lost.
Not advice. Definitions are for understanding, not instruction. Nothing here is financial, legal, tax or security advice.