add 'device-bound key'

index.bs

@@ -1092,6 +1092,7 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "S
     [=client-side discoverable credential=] or a [=server-side credential=].
 
 : <dfn>Hardware-bound Device Key Pair</dfn>
+: <dfn>Device-bound Key</dfn>
 : <dfn>Device Private Key</dfn>
 : <dfn>Device Public Key</dfn>
 :: A [=hardware-bound device key pair=] is a [=[RP]=]-specific and [=user credential=]-specific public key pair created upon a [=[RP]=]'s request via the [=devicePublicKey=] [=WebAuthn extension=].