echelin

== Welsh == === Etymology === echel (“axle”) +‎ -in === Noun === echelin f (plural echelinau) (mathematics) axis Synonym: (dated) echel ==== Derived terms ==== echelin X echelin Y echelin Z echelinol (“axial”) === Further reading === R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke, et al., editors (1950–present), “echelin”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies