Lewis Short
(adj.adv.) : līnĕālis, e, adj.linea
* Consisting of lines, made with lines, lineal (post-class.): ambitus lineales,Amm. 22, 16, 7.—Hence, adv.: līnĕālĭter, in the manner of lines, by means of lines: quos (circulos) linealiter feci,Mart. Cap. 8, § 834.
Charlton T. Lewis, Charles Short, A Latin Dictionary