adj.
Equivalent in effect or value: a request tantamount to a demand.
[From obsolete tantamount, an equivalent, from Anglo-Norman tant amunter, to amount to as much : tant, so much, so great (from Latin tantum, neuter of tantus , from tam, so) + amunter, to amount to, variant of Old French amonter. See amount.]
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.
