Spectra

How to spell spectra

7 letters · 2 syllables

How to pronounce spectra

Say the part in capitals loudest.

What does spectra mean?

1. nounThe plural of spectrum: bands of colours or distributions of values arranged across a continuous range.

Spectra in a sentence

• The physics lab compared the emission spectra of several gases.

• Different stars produce distinct light spectra that reveal their composition.

Where does spectra come from?

Language of origin: Latin

This is the plural of 'spectrum', which English took directly from the Latin spectrum, a noun meaning 'an appearance', 'an image', or 'an apparition'. That Latin word was built on the verb specere, meaning 'to look at' or 'to behold', the same root that gives us 'inspect', 'spectacle', and 'spectator'. When the word entered English in the 1600s it kept its Latin neuter plural form, so the plural of spectrum became spectra rather than the regular English 'spectrums'. Scientists adopted it for the band of colours produced when light is split through a prism, and the term later spread to any distribution of values arranged by some measurable quantity, such as a sound or radiation spectrum. The unusual -a ending is the spelling trap: it is a genuine Latin plural, so writers who expect an English -s sometimes get it wrong.

How the word is built

• spectr- (from Latin spectrum: appearance, image)
• -a (Latin neuter plural ending)