principal plane


noun Optics.

a plane that is perpendicular to the axis of a lens, mirror, or other optical system and at which rays diverging from a focal point are deviated parallel to the axis or at which rays parallel to the axis are deviated to converge to a focal point.

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LEARN THE SPANISH WORDS FOR THESE COMMON ANIMALS!

Are you learning Spanish? Or do you just have an interest in foreign languages? Either way, this quiz on Spanish words for animals is for you.
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How do you say “cat” 🐈 in Spanish?
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021