isinglass
Concise Oxford English Dictionary © 2008 Oxford University Press:
isinglass /ˈʌɪzɪŋˌglɑːs/
▶noun
- 1 a kind of gelatin obtained from fish, especially sturgeon.
- 2 chiefly US mica or a similar material in thin transparent sheets.
'isinglass' also found in these Oxford entries:

