adverb
thereat
thair-AT/ðɛrˈæt/
At that place or occasion.
The dispute occurs at the doorway, and everyone gathers thereat.

Etymology
There supplies the reference and at locates something in relation to it: 'at that place.' The reference can also be a time or event, giving 'at that time' or 'at that event.'
In context
Let me see, then, what thereat is, and this mystery explore.
leads to destruction, and many there be which go in thereat: because strait is the gate,
More examples
- The deed describes the land and all buildings located thereat.
- The annual meeting begins at noon, and members vote thereat.
- The notice announces a hearing and requires your presence thereat.