Where*at" (?), adv.
1.
At which; upon which; whereupon; -- used relatively.
They vote; whereat his speech he thus renews.
Milton.
Whereat he was no less angry and ashamed than desirous to obey Zelmane.
Sir P. Sidney.
2.
At what; -- used interrogatively; as, whereat are you offended?
© Webster 1913.