Astylen or Astyllen: How To spell?

The word Astylen is misspelled against Astyllen, a noun meaning "A small dam to prevent free passage of water in an adit or level."

Astyllen has double "ll" is mispronounced as "l"
Remember double 'LL' in between the strings asty & en which should not be misspelled with single 'L'
Wrong Spelling:  asty-l-en 
Correct Spelling:  asty-ll-en 
Explore spell check of Astyllen to spell without errors.