To coat something with a thin layer of silver. Also, to become shiny like silver.
Silvered things can seem fancy or special.
Examples:
She silvered the mirror to make it shiny.
The moon silvered the water.
The sun silvered the clouds.
He silvered his shoes to make them look special.
The magician's wand silvered in the light.
The old ring silvered and sparkled in the sun.