状 (zhuàng, 'shape') is a productive suffix that converts a noun into an adjective meaning '...-shaped':
环状 ring-shaped,
树状 tree-shaped,
球状 spherical,
网状 net-like,
块状 block-shaped. Most are technical/scientific descriptors;
环状 itself shows up constantly in geography (
环状岛礁 atoll), biology (
环状DNA), and traffic (
环状路线 circular route).
