annular, tricuspid valve, acetabulum, tamponade, coronary sinus, pulmonary vein, subclavian artery, urethra, pulmonary artery, torus, bleb, periosteum, spermatic cord, perforations, dural, anastomosis, uterine cavity, pericardium, subarachnoid space, anal canal, diverticula, inferior vena cava, fibrocartilage, peritoneal cavity, descending aorta, ostia, interspace, capsular, acromion, intervertebral disc, foramen, sigmoid colon, cecum, intraventricular, ureter, hyaline cartilage, lateral epicondyle, uterine artery, aortic arch, embolus, peritoneum, mediastinum, intervertebral, alveoli, bursa, lymphatics, semipermeable membrane, pleural, laparotomy, bronchi, abdominal cavity, popliteal artery, intervertebral disk, intima, pelvic cavity, pedicle, tubules, trabeculae, distal, flange, permeabilities, femoral vein, atrial, basilar artery, inguinal, femoral, ascending aorta, commissure, myocardium, septal, umbilical vein, thoracic aorta, mucosa, cerebrospinal fluid, pericardial sac, overpressure, left ventricle, epiglottis, epiphysis, adventitia, endotracheal tube, parenchyma, dura mater, vena cava, atrioventricular, synovial fluid, venous blood, cavernous sinus, seafloor, thrombus, intraocular, condyle, vertebral artery, splenic artery, brachial artery, angulation, coronary artery, valve, arterioles, suprarenal, diaphysis, spinal canal, annuli, lamina, lamella, posterior, ring, septum, ampulla, frontal, furrow, meniscus, thorax, band, bundle, capsule, eyelid, lamellae, macula, orifice, alveolus, basal, cancellous, lumen, periarticular, alveolar, brain, cavity, corona, corresponding, endocardial, focal, globulin, matrix, membrane, metaphyseal, mullite, nucleus, opercular, porosity

fairy circle, fairy ring

armillaria, entoloma, genus armillaria, genus entoloma, genus pholiota, genus russula, partial veil, pholiota, russula, velum

partial veil, velum

plant part, toroid

anchor ring, anulus, doughnut, halo, ring