Nonvitreous tile | Article about nonvitreous tile by The Free Dictionary
Ceramic tile having a degree of vitrification evidenced by a water absorption greater than 3%; an exception is nonvitreous floor and wall tile, which has a water absorption above 7% but less than 18%.
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2) Especially nonvitreous tiles
are used indoors as wall tiles and semivitreous tiles are only used indoors, on walls and floors.