Hypertext Webster Gateway: "helicoidal"
From Webster's Revised Unabridged Dictionary (1913) (web1913)
Helicoidal \Hel`i*coid"al\, a.
Same as {Helicoid}. -- {Hel`i*coid"al*ly}, adv.
Additional Hypertext Webster Gateway Lookup
Gateway by dict@stokkie.net
stock only wrote the gateway and does not have any control over the contents;
see the Webster Gateway FAQ,
and also the Back-end/database links and credits.