needle, pin, staple, stinger
針 centers on a thin, pointed metal object used for piercing or fastening: a needle, pin, staple, or stinger.
針 combines 金 (metal) and 十 (needle shape), suggesting a metal needle. The right side 十 likely represents the needle itself rather than the number ten.
The left side 金 means metal, and the right side 十 looks like a needle with its sharp point. Together they form a metal needle.
For シン, imagine a thin metal needle shining under a light: shin -> シン, and the needle gleams.
policy; course; plan (of action); principle
needle; pin
needle (compass, gauge, etc.); hand (clock); indicator; pointer; index
compass
wire
hedgehog (any mammal of family Erinaceidae)
porcupinefish (Diodon holacanthus); balloonfish
course; direction
fish hook
conifer; needle-leaved tree
second hand (of clock)
lightning rod
firing pin
inspection of a meter; reading a meter
hook; crochet hook; crochet needle
pincushion
Japanese halfbeak (Hemiramphus sajori); stickleback
pincushion
short hand; hour hand
seamstress