phlo·i·on·ic acid \|flōē|änik-\noun Etymology:phloionic from Greek phloios bark + English -onic : a crystalline hydroxy acid [−CH(OH)(CH2)7COOH]2 that is among the acidic products formed by alkaline hydrolysis of cork; 9,10-dihydroxy-octadecane-dioic acid — see suberin