Is it ensure, insure, or assure?
"pertaining to an axis," by 1825, from axis + -al (1). Related: Axially.
axial ax·i·al (āk'sē-əl)adj.
Relating to or characterized by an axis; axile.
Relating to or situated in the head and trunk region of the body.
Relating to or parallel with the long axis of a tooth.