perpendicular to the centre of the valve face of a diatom

(clocks, mechanics) The contrivance in a timepiece (winding wristwatch) which connects the train of wheel work with the pendulum or balance, giving to the latter the impulse by which it is kept in ...

The lee face of a sand dune where the surface is at the angle of repose for sand (33–35°).

(transitive) To stupefy, paralyze or petrify.