inositol UK /ʌɪˈnəʊ.sɪ.tɒl/US /ɪˈnoʊ.səˌtɒl/ noun1 •A simple carbocyclic sugar (hexahydroxycyclohexane; chemical formula: C₆H₁₂O₆) which occurs in animal and plant tissue. Once treated as part of the vitamin B complex, but is not a vitamin as it can be synthesized by the body. formsinositols