Webster's Revised Unabridged Dictionary · 1913

Thereat

Thereat , adverb

1.
At that place; there.
Wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat. — Matt. vii. 13
2.
At that occurrence or event; on that account.
Every error is a stain to the beauty of nature; for which cause it blusheth thereat. — Hooker