<n0:ComplexDefinition xmlns:n0="http://ncicb.nci.nih.gov/xml/owl/EVS/ComplexProperties.xsd#"><n0:def-definition>A cyclic compound. any compound in which the constituent atoms, or any part of them, form a ring. Used mainly in organic chemistry. SYN closed chain compound, ring compound.</n0:def-definition><n0:def-source>NCI</n0:def-source></n0:ComplexDefinition>