1. 1. Absorbed in thought; engrossed.
   2. Excessively concerned with something; distracted.
2. Formerly or already occupied.
3. Already used and therefore unavailable for further use. Used of taxonomic names.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.