caustic soda

= sodium hydroxide (sodium).

cattle-grid, catty, catwalk, Caucasian, caucus, caught, caul, cauldron (also caldron), cauliflower, cauliflower cheese, cauliflower ear, caulk, caulk (also esp US calk), causal, causality, causation, causative, cause, causeway, caustic, caustically, cauterize, cauterize, cauterise, caution, cautionary, cautious, cautiously, cautiousness, cavalcade, cavalier, cavalry, cave, cave in, cave-dweller, cave-in, caveat, caveman, cavern, cavernous, caviare (also caviar),