Permeable

Part of speech: adjective

Pronunciation: /ˈpɜːmiəbəl/

Definitions

1. Able to let substances, including liquids and gases, flow through it
2. Characterized by the property to allow various materials, especially fluids, to pass or penetrate
3. Capable of being penetrated by fluids or gases, letting them move through easily

Etymology: Latin "permeāre" meant "to pass through," built from "per" ("through") and "meāre" ("to go, pass"), the same verb that gave English "meander" in its wider sense of winding passage. The adjective "permeābilis" described something that could be passed through, and English borrowed it in Middle English as "permeable," with the spelling and sense still close to the Latin original. Because the word is a direct borrowing rather than a later coinage, its core meaning has barely shifted in six or seven centuries: a material is permeable when fluid or gas can pass through its pores or gaps. Scientists and writers later extended it figuratively to boundaries, such as a permeable border or a permeable mind, but the physical sense of letting something seep through remains the anchor.

Synonyms: porous, pervious, penetrable, allowing passage, accessible

Antonyms: impermeable, impenetrable, sealed, blocked, closed