porous

/ˈpɔrəs/

/ˈpɔrɪs/

If something is full of tiny holes or openings, you can describe it as porous. A sponge is porous, and if the border between countries is open for anyone to cross easily, it too can be called porous.

You can see the word pore — meaning "a tiny opening" — in porous. When potters make a mug, they use special glazes to seal the porous clay, which otherwise would absorb the liquid you put in the mug. This meaning has expanded so porous can describe any barrier that allows easy passage in and out, like the porous border between two countries that allows residents to move easily between them.

Definitions of porous

1. adjective

   full of pores or vessels or holes
   synonyms: poriferous

   porose

   forming a continuous series of pores

   antonyms:

   nonporous

   not porous; especially not having vessels that appear as pores
2. adjective

   allowing passage in and out
   “our unfenced and largely unpoliced border inevitably has been very porous”

   synonyms: holey

   leaky

   permitting the unwanted passage of fluids or gases
3. adjective

   able to absorb fluids
   “the partly porous walls of our digestive system”

   “compacting the soil to make it less porous”

   synonyms:

   permeable

   allowing fluids or gases to pass or diffuse through