What does Sable mean?
A word-name from 'sable', which in heraldry denotes the colour black; derived via Old French from the dark-furred sable marten. Note: a vocabulary name, with the 'black' meaning coming from the heraldic term.
What does Dusk mean?
A modern word-name from the English word 'dusk', the darker stage of twilight, ultimately from Old English 'dox / dosc' meaning 'dark-coloured, dusky'. Note: used as a vocabulary name rather than a traditional given name.