Definition of "incommensurable" [in•com•men•su•ra•ble]

• Impossible to measure or compare. (adjective)
• Lacking a common quality on which to make a comparison. (adjective)
• Mathematics Having no common measure or number of which all the given lengths or measures are integral multiples. (adjective)
• Mathematics Having an irrational ratio. (adjective)
• One that is incommensurable. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "It might seem as though the idea of incommensurable alternatives does not really make sense."
• ""incommensurable" -- they sail past each other; the two sides are talking about different things."
• "The "loving anachronism" Steven Jones's happy phraseof reading Shelley with and against historical moments and political crises that are irreducibly unique and particular, "incommensurable" (Jones again), confirms those lines in Adonais (stanza 46) about the "fire" outliving the "parent spark.""