djine -jin- gismu

x1 is a ring/annulus/torus/circle [shape/form] of material x2, inside diam. x3, outside diam. x4.

Also ellipse, oval (= jincla); (usage has been for near-circles, such as tight spirals, even if not closed loops). Also band, belt, encircle (= jinsru). See also clupa, cukla, dasri, karli, sovda, sruri, konju.

In notes:

x1 is a loop/circuit of x2 [material].
x1 is round/circular [2-dimensional shape/form]; x1 is a disk/circle/ring.
x1 is a ribbon/tape/strip/band/stripe of material x2.
x1 is a collar/ring/belt/band around/surrounding x2 made of material x3.
x1 is a cone [shape/form] of material x2 with vertex x3.
x1 is an egg/ovum/sperm/pollen/gamete of/from organism [mother/father] x2.
x1 encircles/encloses/is surrounding x2 in direction(s)/dimension(s)/plane x3.
x1 is a ring/torus/oval [round, closed shape/form], composed of material x2, of inner diameter x3 and outer diameter of x4
j1 is a ring on finger j2=d1.
x1 is a region/room/volume of space which is shaped like a washer (or thin or flattened torus/toroid), between inner disk/sphere x2 and outer disk/sphere x3, defined by midplane x4, and containing x5.
x1=d1=s1 is a bearing of material x2=d2, supporting x3=s2 against force/opposition x4=s3
x1 is a planetary ring, region defined by a 'cloud' or 'constellation' of satellites, asteroid belt, generalized Kuiper belt, generalized Oort cloud, or other such belt or cloud or region in stellar/star or planet-centered/planetary ring system x2, extending over and throughout region x3 or being of shape (including size/dimensions) x3, including/containing objects or points of interest x4, with other properties/orbital parameters x5.