Account: The owner of a HNS domain name. Generally, the owner would be a Hedera Account ID.
Domain (Name): A HNS identifier such as hns.hbar. A domain may consist of multiple parts, called subdomains, separated by dots.
Namehash: The algorithm used to process a HNS domain name and returns an object with a human-readable domain name, a subdomain hash, and a top-level domain hash.
Operator: The account that may edit the records of a domain name.
Subdomain (SLD): An individual component of a domain name, such as hns in hns.hbar.
Subdomain Hash: The keccak256 hash of an individual subdomain.
Top-level Domain (TLD): The last part of a domain name, such as hbar in hns.hbar.
Owner: The owner of a domain is the entity referenced in the HNS registry's account_id field. Also see Account.
Registrar: A registrar is a contract responsible for allocating subdomains. The owner field of the registry points to registrars.
Registration: A registration is a registrar's record of an account's ownership of a domain name.
Registrant: See Account.
Registry: The HNS smart contracts and HCS topic IDs that maintains a mapping from domain name to account and domain registration details (e.g. expiration, namehash, etc).
Resolver: The HNS resolver is in the form of an API (coming soon) and an SDK that returns one or more domain names owned by a specified account.