Scale
A scale was a small plate growing off the skin of several animals including reptiles.

According to Malcolm Reed, he described the first Novan he'd seen as "appearing a couple of meters tall, biped, with odd-looking scales." ()

In 2153, Doctor Phlox was studying epithelial cells of the Xindi pilot who crash landed with the Xindi probe on Earth under his microscope and noted his colorful skin pigmentation. After sharing his findings with T'Pol, the Vulcan noted that these epithelial cells look more like scales. This led to the conclusion that the pilot was some sort of a Xindi-Reptilian. ()

Ktarians were scaled. In 2372, Samantha Wildman was advised by The Doctor that she could breastfeed Naomi Wildman immediately, but would have to cease around three or four weeks later, as Naomi's incisors would erupt by then, and Samantha lacked the scales of Ktarian women. ()

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Anatomy