Definition of "canthus"

the lowly East with its deer head (dark trace of long tear at inner canthus

1955, Vladimir Nabokov, Lolita

I could sit here while the milk makes white shadows in its glass, while darkness mutters behind the window, and wait for a tear to show itself in the creased canthus of your eye.

2004, Andrew Sean Greer, The Confessions of Max Tivoli, Farrar, Straus and Giroux, page 263

A ground electrode located between Fpz and Fz. The electro-oculogram (EOG) was recorded bipolarly from two electrodes placed at the outer canthi of the right eye and below the left eye.

2015 August 26, “Effects of Relaxing Music on Mental Fatigue Induced by a Continuous Performance Task: Behavioral and ERPs Evidence”, in PLOS ONE‎