- A small pack or package; a little bundle or parcel; as, a packet of letters, a packet of crisps, a packet of biscuits.
- (networking) A small fragment of data as transmitted on some types of network, notably Ethernet networks.
- (botany) A specimen envelope containing small, dried plants or containing parts of plants when attached to a larger sheet.
- (nautical) Originally, a vessel employed by government to convey dispatches or mails; hence, a vessel employed in conveying dispatches, mails, passengers, and goods, and having fixed days of sailing; a mail boat. Packet boat, ship, vessel.
- (South Africa) A plastic bag.
- (transitive) To send in a packet or dispatch vessel.
- (transitive) To make up into a packet or bundle.
- (transitive, Internet) To subject to a denial-of-service attack in which a large number of data packets are sent.
- (intransitive) To ply with a packet or dispatch boat.