Balista or Ballista: How To spell?
The word Balista is misspelled against Ballista, a noun meaning "An ancient military engine, in the form of a crossbow, used for hurling large missiles."
Ballista has double "ll" is mispronounced as "l"Remember double 'LL' in between the strings ba & ista which should not be misspelled with single 'L'
Wrong Spelling:  ba-l-ista  Correct Spelling:  ba-ll-ista 
Find more wrongly spelled words of Ballista to spell it well.