- 1. A cone-shaped structure. 2. Part of the apical complex characteristic of the protozoan subphylum, Apicomplexa; seen in sporozoites, merozoites, or other developmental stages of sporozoans, less well developed in the piroplasms (families Babesiidae and Theileriidae). The function of the c. is unknown, but it is thought to be an organelle of penetration into the host cell, possibly aided by a protrusible form of the c.. [G. konoeides, cone-shaped]- Sturm c. in optics, the pattern of rays formed after passage through a spherocylindrical combination.
* * *co·noid 'kō-.nȯid or co·noi·dal kō-'nȯid-əl adj shaped like or nearly like a coneconoid n a cone-shaped structure esp a hollow organelle shaped like a truncated cone that occurs at the anterior end of the organism in some developmental stages of some sporozoans (as of the genus Sarcocystis)
* * *co·noid (koґnoid) [cono- + -oid] 1. resembling or shaped like a cone. 2. an electron-dense, protrusible, hollow region surrounded by polar rings and composed of spirally coiled microtubules that forms part of the apical complex of apicocomplexan protozoa.
Medical dictionary. 2011.