Definition of "barrier" []

• A structure, such as a fence, built to bar passage. (noun)
• Something immaterial that obstructs or impedes: Intolerance is a barrier to understanding. See Synonyms at obstacle. (noun)
• Physiology A membrane, tissue, or mechanism that blocks the passage of certain substances. (noun)
• Ecology A physical or biological factor that limits the migration, interbreeding, or free movement of individuals or populations. (noun)
• A boundary or limit. (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.

• "I think the term barrier is a more accurate description of a concept David is alluding to."
• "It's about attitudes that the barrier is the disability."
• "I was given a phone number and reached a Ryan who proceeds to tell me that what I call a barrier on my porch is not considered a barrier."