a silver-white metallic element of the platinum group that resembles platinum; occurs in some copper and nickel ores; does not tarnish at ordinary temperatures and is used (alloyed with gold) in jewelry
something that provides an important central source for growth or development; "the taproot of his resentment"; "genius and insanity spring from the same taproot"
(botany) main root of a plant growing straight downward from the stem