1.
scale (of a fish or reptile)
The small, flat, overlapping plates that cover the skin of fish and reptiles.
Writing
Usually written in hiragana (うろこ) or kanji (鱗). The kanji is relatively uncommon in everyday writing.
Common expressions
目から鱗が落ちる (literally, "scales fall from one's eyes") means to have a sudden realization or to see something in a completely new way. This is one of the most well-known expressions using 鱗.