Lost in thought or inattentive to surroundings; also, considered apart from concrete details or specific instances (as in abstract ideas).
From abstract (Latin abstractus 'drawn away,' past participle of abstrahere: ab- 'away' + trahere 'to draw') plus -ed. Means either mentally 'drawn away' or conceptually separated.
When a mathematician is 'abstracted,' they've literally mentally removed themselves from the concrete world—they're thinking about abstract concepts like infinity or impossible geometries, which is why brilliant mathematicians sometimes seem absent-minded!
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