Plain English Meaning
Something is abeam when it's directly off your wing — out to your side, not in front of you and not behind you.
Full Definition
A position approximately 90 degrees to the left or right of the aircraft's longitudinal axis. A point or object is abeam when it lies off the wingtip, neither ahead of nor behind the aircraft. The term indicates a relative bearing only and does not specify distance from the point.
Context Anchor
Used in traffic patterns, position reports, and navigation instructions when describing where the aircraft is relative to a runway, , landmark, or .