ˈtrōnə noun
( -s )
Etymology: Swedish, probably from Arabic naṭrūn natron — more at natron
: a gray-white or yellowish white monoclinic mineral Na 3 H(CO 3 ) 2 .2H 2 O consisting of a hydrous acid sodium carbonate in crystals or fibrous or columnar masses as a deposit from various soda-brine springs and lakes (hardness 2.5-3, specific gravity 2.11-2.14)