From The Collaborative International Dictionary of English v.0.48:
Sond \Sond\, Sonde \Sonde\, n. [AS. sand. See Send, v. t.]
1. That which is sent; a message or messenger; hence, also, a
visitation of providence; an affliction or trial. [Obs.]
[1913 Webster]
Ye have enough, parde, of Goddes sond. --Chaucer.
[1913 Webster]
2. (Rocketry) a rocket or balloon sent into the upper
atmosphere to measure atmospheric conditions or other
phenomena at altitudes unattainable by aircraft.
[PJC]