Definition of "anadem"

Ada, on the grass, kept trying to make an anadem of marguerites for the dog while Lucette looked on, munching a crumpet.

1969, Vladimir Nabokov, Ada or Ardor, Penguin, published 2011, page 67

As she held high the Staff, she caught the early sunlight. Her hair shone about her like an anadem, and the golden Ranyhyn bore her up like an offering to the wide day.

1978, Stephen Donaldson, The Illearth War