Definition of "lamina" []

• A thin plate, sheet, or layer. (noun)
• Botany The expanded area of a leaf or petal; a blade. (noun)
• Botany The bladelike part of a kelp. (noun)
• A thin layer of bone, membrane, or other tissue. (noun)
• Zoology A thin scalelike or platelike structure, as one of the thin layers of sensitive vascular tissue in the hoof of a horse. (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.

• "You know the properties of thin laminae: each ray reflected from such a lamina is formed by the superposition of a ray reflected from the front side of the lamina on a ray reflected from the rear side."
• "For each elementary colour these rays add together or subtract from one another according to a classical formula, depending on whether they are in phase or out of phase; in particular, there is extinction when the thickness of the lamina is an even multiple of one quarter of the wavelength, and there is maximum reflection when it is an odd multiple."
• "On the inner surface of the lamina choriocapillaris is a very thin, structureless, or faintly fibrous membrane, called the lamina basalis; it is closely connected with the stroma of the choroid, and separates it from the pigmentary layer of the retina."