Directional Indicators

[jdroscha@...]

As the release of the first commercially available piecepacks (from 
Mesomorph Games) seems imminent, I've realized I overlooked one bit 
of terminology they may wish to include in their accompanying 
rulebooklet: what to call that little mark on each side of a coin 
that can be used to indicate direction or rotation of the coin?

Tick mark?

Facing mark?

Any other suggestions that would be generic and easy to remember?

Are there any applicable standard terms already used in, say, 
wargaming?

Thanks,
James