偏芯[henshin] eccentricity (in mechanics, electronics, etc.)
燈芯[toushin] (lamp) wick
帯芯[obishin] thick obi sash
摘芯[tekishin] thinning (buds and branches)
芯地[shinji] padding

替え芯[kaeshin] spare lead
鉛筆の芯[enpitsunoshin] lead of a pencil
硬の芯[kounoshin] hard pencil lead
林檎の芯[ringonoshin] core of an apple

運針[unshin] handling the needle
検針[kenshin] inspection of a meter
絹針[kinubari] needle for silkwork
行動方針[koudouhoushin] course of action
指針[shishin] needle (of a compass, etc.)

自主指針[jishushishin] independent guideline
畳針[tatamibari] tatami needle
針鰻[hariunagi] elver (type of eel)
針金[harigane] wire