The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
sweid-
DEFINITION:
Sweat; to sweat. I. O-grade form *swoid-.1.sweat, from Old English swtan, to sweat, from Germanic *swaitaz, sweat, with its denominative *swaitjan, to sweat. 2. Suffixed form *swoid-os-.sudorific; sudoriferous, from Latin sdor, sweat. 3. O-grade form *swoid--.sudatorium, suint; exude, transude, from Latin sdre, to sweat. II. Suffixed zero-grade form *swid-r-os-.hidrosis, from Greek hidrs, sweat. (Pokorny 2. seid- 1043.)
tan, to sweat, from Germanic *swaitaz, sweat, with its denominative *swaitjan, to sweat. 2. Suffixed form *swoid-os-. sudorific; sudoriferous, from Latin s
dor, sweat. 3. O-grade form *swoid-
-. sudatorium, suint; exude, transude, from Latin s
s, sweat. (Pokorny 2. s
eid- 1043.) 
