sonde
sonde \'sa:nd\ n [F, lit., sounding line - more at SOUND] : any of various devices for testing physical and meteorological condition s at high altitudes above the earth's surface
Webster's English Dictionarysonde \'sa:nd\ n [F, lit., sounding line - more at SOUND] : any of various devices for testing physical and meteorological condition s at high altitudes above the earth's surface