glasswort n bushy plant of Old World salt marshes and sea beaches having prickly leaves; burned to produce a crude soda ash n fleshy maritime plant having fleshy stems with rudimentary scalelike leaves and small spikes of minute flowers; formerly used in making glass Synonym(s) saltwort barilla kali kelpwort Salsola kali Salsola soda samphire Salicornia europaea