perpendicular to the centre of the valve face of a diatom

(transitive) To stupefy, paralyze or petrify.

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

(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 ...