The Collaborative International Dictionary of English v.0.48:

Jupiter \Ju"pi*ter\, n. [L., fr. Jovis pater. See Jove.]
   [1913 Webster]
   1. (Rom. Myth.) The supreme deity, king of gods and men, and
      reputed to be the son of Saturn and Rhea; Jove. He
      corresponds to the Greek Zeus.
      [1913 Webster]

   2. (Astron.) One of the planets, being the fifth from the
      sun, the brightest except Venus, and the largest of them
      all, its mean radius being about 43,345 miles (69,758
      kilometers), almost exactly one-tenth that of the sun. It
      revolves about the sun in 4,332.6 days, at a mean distance
      of 5.2025 from the sun (778,140,000 km), the earth's mean
      distance (the astronomical unit) being taken as unity. It
      has a mass of 1.901 x 10^27 kg, about one-thousandth
      that of the sun, and more than the remainder of the
      planets combined. It has an average solar day equal to
      9.842 earth hours. The rapid revolution causes a
      noticeable flattening at the poles; the diameter at the
      equator is 71,370 km, and at the poles 66,644 km. --HCP61
      [1913 Webster +PJC]

   Jupiter's beard. (Bot.)
      (a) A South European herb, with cymes of small red
          blossoms (Centranthus ruber).
      (b) The houseleek (Sempervivum tectorum); -- so called
          from its massive inflorescence, like the sculptured
          beard of Jove. --Prior.
      (c) the cloverlike Anthyllis Barba-Jovis.

   Jupiter's staff (Bot.), the common mullein; -- so called
      from its long, rigid spike of yellow blossoms. Jupon

WordNet (r) 3.0 (2006):

Jupiter
    n 1: the largest planet and the 5th from the sun; has many
         satellites and is one of the brightest objects in the night
         sky
    2: (Roman mythology) supreme god of Romans; counterpart of Greek
       Zeus [syn: Jupiter, Jove]

The Free On-line Dictionary of Computing (19 January 2023):

jupiter

   To kill an IRC robot or user and then take its place by
   adopting its nick so that it cannot reconnect.  Named after
   a particular IRC user who did this to NickServ, the robot in
   charge of preventing people from inadvertently using a nick
   claimed by another user.

   [Jargon File]

   (1994-11-23)


The Jargon File (version 4.4.7, 29 Dec 2003):

jupiter
 vt.

    [IRC] To kill an IRC bot or user and then take its place by adopting
    its nick so that it cannot reconnect. Named after a particular IRC user
    who did this to NickServ, the robot in charge of preventing people from
    inadvertently using a nick claimed by another user. Now commonly shortened
    to jupe.

    K