芯

wick; marrow; staple (for stapler); (pencil) lead; stuffing; pith

core; heart; centre; center

pistil (of a flower)

stamen

mentally strong; strong-willed

padding; lining; foundation

pencil lead case (for a mechanical pencil)

lead pointer (for a clutch pencil); lead sharpener

Idiomatic expression

to get to the heart of the matter; to get to the core

Idiomatic expression; Sports

to hit (a ball) with the sweet spot (of a golf club, baseball bat, etc.)

Engineering

centering; center alignment

continued alertness; unrelaxed alertness; remaining on one's guard; being prepared for a counterstroke

Esp. 残身

follow-through (e.g. in archery)

Orig. meaning

lingering affection; attachment; regret; regrets; reluctance

center of a flower (centre); pistils and stamens

dead center

lead of a pencil

(lamp) wick

Colloquial; From シャーペン + 芯

mechanical pencil lead

apple core; core of an apple

wick of a candle

dead center (of a baseball bat); sweet spot

spare pencil lead; pen refill (cartridge); replacement wick (e.g. of a lantern)

Chinese water spinach (Ipomoea aquatica); ong choy; kang kong; water morning glory; water convolvulus; swamp cabbage; hung tsai; rau muong; pak boong; swamp morning-glory

thick obi sash; sash padding

thinning (buds and branches)

eccentricity (in mechanics, electronics, etc.)

Electricity, elec. eng.

core wire; conductor

staple (for a stapler)

collar core (stiff fabric, etc. inside a collar)