Source : Webster's Revised Unabridged Dictionary (1913)

Packet \Pack"et\, n. [F. paquet, dim. fr. LL. paccus, from the
   same source as E. pack. See {Pack}.]
   1. A small pack or package; a little bundle or parcel; as, a
      packet of letters. --Shak.

   2. 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}, or {vessel}. See {Packet}, n., 2.

   {Packet day}, the day for mailing letters to go by packet; or
      the sailing day.

   {Packet note} or {post}. See under {Paper}.

Packet \Pack"et\, v. t. [imp. & p. p. {Packeted}; p. pr. & vb.
   n. {Packeting}.]
   1. To make up into a packet or bundle.

   2. To send in a packet or dispatch vessel.

            Her husband Was packeted to France.   --Ford.

Packet \Pack"et\, v. i.
   To ply with a packet or dispatch boat.

Source : WordNet®

packet
     n 1: a collection of things wrapped or boxed together [syn: {package},
           {bundle}, {parcel}]
     2: (computer science) a message or message fragment
     3: a small package or bundle
     4: a boat for carrying mail [syn: {mailboat}, {mail boat}, {packet
        boat}]

Source : Free On-Line Dictionary of Computing

packet
     
        The unit of data sent across a {network}.  "Packet" is a
        generic term used to describe a unit of data at any layer of
        the {OSI} {protocol stack}, but it is most correctly used to
        describe {application layer} data units ("{application
        protocol data unit}", APDU).
     
        See also {datagram}, {frame}.
     
        (1994-11-30)