イン, とら, とも, のぶ
sign of the tiger, 3-5AM, third sign of Chinese zodiac
JLPT1 G13 S0 F1975
The relevant oracle bone form of this character combines 矢# arrow + a pair of hands → straighten an arrow. A seal inscription form adds 宀 roof/building, creating 寅, the original sense of which was to straighten/stretch and stand to one's full height, inside a building. *Tiger* (as the *third sign of the Chinese zodiac*) and *3 A.M. to 5 A.M.* are borrowed meanings.
[Full Kanji Etymology List]