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1. Admitting the passage of gas or liquid through pores or interstices.
2. Easily crossed or penetrated: a porous border.
[Middle English, from Old French poreux, poros, from Medieval Latin porōsus, from Latin porus, passage; see pore2.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.