Medical Dictionary
barrier
noun bar·ri·er \ˈbar-ē-ər\
Medical Definition of BARRIER
1
: a material object or set of objects that separates, demarcates, or serves as a barricade—see blood-brain barrier, placental barrier
2
: a factor that tends to restrict the free movement, mingling, or interbreeding of individuals or populations <behavioral and geographic barriers to hybridization>
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