Derivation Path

The notation that identifies a specific key within an HD wallet's tree — for example `m/84'/0'/0'/0/0`. Each segment selects a child key: `purpose'` (script type), `coin_type'`, `account'`, `change` (external vs internal), and `address_index`. Different wallets default to different paths, which is the most common cause of 'my seed is right but the balance is missing' after a restore — the seed is fine, the path is wrong.