An Etymological Dictionary of Astronomy and Astrophysics

1. In geophysics, any penetration of the natural environment for scientific observation.
   
2. In meteorology, a free, unmanned balloon carrying instruments aloft to make atmospheric measurements, esp. a radiosonde balloon.
   
3. The measurement of the depth of water beneath a vessel.

Etymology (EN): From Fr. sonder, → sonde.

Etymology (PE): From gomâné, → sonde, + zani verbal noun of zadan “to do; to strike, beat; to play an instrument” (Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- “to strike, hit, smite, kill” (jantar- “smiter”); cf.
Skt. han- “to strike, beat” (hantar- “smiter, killer”);
Gk. theinein “to strike;” L. fendere “to strike, push;” Gmc. *gundjo “war, battle;” PIE *g^when- “to strike, kill”).