axisyoudaoicibaDictYouDict[axis 词源字典]
axis: [14] Axis is at the centre of a complex web of ‘turning’ words. Besides its immediate source, Latin axis, there were Greek áxōn, Sanskrit ákshas, and a hypothetical Germanic *akhsō which produced Old English eax ‘axle’ as well as modern German achse ‘axle, shaft’ and Dutch as; and there could well be a connection with Latin agere (source of English act, agent, etc) in the sense ‘drive’.

Also related is an unrecorded Latin form *acslā, which produced āla ‘wing’ (source of English aileron and aisle); its diminutive was axilla ‘armpit’, from which English gets the adjective axillary [17] and the botanical term axil [18].
=> aileron, aisle, axil[axis etymology, axis origin, 英语词源]
axis (n.)youdaoicibaDictYouDict
1540s, "imaginary straight line around which a body (such as the Earth) rotates," from Latin axis "axle, pivot, axis of the earth or sky," from PIE *aks- "axis" (cognates: Old English eax, Old High German ahsa "axle;" Greek axon "axis, axle, wagon;" Sanskrit aksah "an axle, axis, beam of a balance;" Lithuanian aszis "axle"). Figurative sense in world history of "alliance between Germany and Italy" (later extended unetymologically to include Japan) is from 1936. Original reference was to a "Rome-Berlin axis" in central Europe. The word later was used in reference to a London-Washington axis (World War II) and a Moscow-Peking axis (early Cold War).