Definition of "spectra" [spectra]

• A plural of spectrum. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "These ocular spectra are of four kinds: 1st, Such as are owing to a less sensibility of a defined part of the retina; or _spectra from defect of sensibility. _ 2d, Such as are owing to a greater sensibility of a defined part of the retina; or _spectra from excess of sensibility_. 3d, Such as resemble their object in its colour as well as form; which may be termed"
• "The plans spectra& spectra plus offer global life insurance coverage and global payout."
• "_Of direct and inverse spectra existing at the same time_; _of reciprocal direct spectra_; _of a combination of direct and inverse spectra_; _of a spectral halo_; _rules to pre-determine the colours of spectra_.a. When an area, about six inches square, of bright pink Indian paper, had been viewed on an area, about a foot square, of white writing paper, the internal spectrum in the closed eye was green, being the reverse spectrum of the pink paper; and the external spectrum was pink, being the direct spectrum of the pink paper."