ˌthōrəˈkästēˌī, ˌthȯr- noun plural
Usage: capitalized
Etymology: New Latin, from thorac- + -ostei (from Greek osteon bone) — more at osseous
in some classifications : an order comprising fishes with the body more or less completely covered by bony plates and the pharyngeal bones and other structures about the head more or less undeveloped and including the sticklebacks, pipefishes, and sea horses