whence \hwens\ (pronoun) - From where?
"Fred apparently was bitten by a scorpion in his office -- whence his complaint about company safety."
Proto-Indo-European had a series of interrogative pronouns (what? when? where?) based on kw- + suffix and demonstrative pronouns (that, then, there) basec on t- + suffixes. The [k] became [h] regularly in Germanic languages while the [t] became [th]. (Although we write our interrrogative pronouns "wh," they are pronounced [hw].) The [h] disappeared in German (was "what?" wann "when?" wo "where?") and in some dialects of English. In Latin, the [kw], spelled "qu" was retained: qui [kwee] "who," quid "what," quando "when." In Slavic languges the [w] was lost, so we get kto "who," kogda "when," kuda "whither" and to "that," togda "then," tam "there."