seltzer
Concise Oxford English Dictionary © 2008 Oxford University Press:
seltzer /ˈsɛltzə/
▶noun dated
- 1 soda water.
- 2 medicinal mineral water from Niederselters in Germany.
– origin C18: alt. of Ger. Selterser, from (Nieder)selters (see above).
'seltzer' also found in these Oxford entries:

