axial vs tertiary

axial

noun
  • A flight feather that appears between the primaries and secondaries on some birds. 

  • A plane parallel to the surface of a tooth. 

adj
  • Belonging to the axis of the body, or to the axis of any appendage or organ 

  • Relating to, resembling, or situated on an axis 

  • In the same direction as the axis, parallel to the axis. 

  • oriented close to the axis running through the centre of a cyclohexane ring, as opposed to equatorial. See w:Axial bond. 

tertiary

noun
  • A tertiary feather; a tertial. 

  • A member of a Roman Catholic third order; a layperson who participates in activities similar to those engaged in by men and women who take religious vows (respectively the first and second orders), and who may wear some elements of an order's habit such as a scapular. 

  • A large stage in some extremely powerful thermonuclear weapons (resembling a greatly-enlarged secondary) which is compressed by the explosion of the secondary until ignition of nuclear fusion takes place, in much the same manner as the secondary is imploded by the primary, and which can allow for the attainment of yields of many tens or even hundreds of megatons, and likely even greater; not used in modern weapons due to a greater focus on the accurate use of sub-megaton weapons, the tremendous size of weapons incorporating a tertiary, and the lack of targets whose destruction would necessitate the use of a three-stage weapon. 

  • Any item considered to be of third order. 

  • Something from the Tertiary Period (the former term for the geologic period from 65 million to 2.58 million years ago). 

  • A tertiary colour. 

adj
  • Of quills: growing on the innermost joint of a bird's wing; tertial. 

  • Of third rank or order; subsequent. 

  • Possessing some quality in the third degree; especially having been subjected to the substitution of three atoms or radicals. 

How often have the words axial and tertiary occurred in a corpus of books? (source: Google Ngram Viewer )