Answer: SCIO

AnswerCrossword Clue
SCIOI know: Lat.
SCIOWord form for "shadow"
SCIOBirthplace of Homer.
SCIOGhost: Comb. form.
SCIOAnother name for Chios.
SCIOShadow: Comb. form.
SCIOAncient city where Homer may have been born.
SCIOKnow: Latin.
SCIOItalian name of Chios.
SCIOShadow: Prefix.
SCIOShadow: Prefix
SCIOShadow: Comb. form
SCIOShadow or ghost: Prefix
SCIOCicero's "I know"