arciform,a.|ˈɑːsɪfɔːm| [mod.f. L. arc-us bow + -iform; cf. F. arciforme.] Bent like a bow, bow-shaped; spec. applied to nerve-fibres passing from the brain to the spinal cord through the medulla oblongata. 1839Todd Cycl.Anat. III. 681/1 The arciform fibres.