Definition of spectra:
(N) :
Spectra: A Book of Poetic Experiments was a small volume of poetry published in 1916 by American writers Witter Bynner, who wrote under the pseudonym "Emanuel Morgan", and Arthur Davison Ficke, who wrote as "Anne Knish."
(N) :
the name of a series of art installations by Ryoji Ikeda which use intense white light as a sculptural material.
(N) :
a professional association of LGBTQIA+ mathematicians.