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

垂迹[suijaku] temporary manifestation by a buddha (in order to save people)
筆迹[hisseki] handwriting
真迹[shinseki] true autograph

事迹[jiseki] evidence
本地垂迹説[honjisuijakusetsu] manifestation theory (holding that Shinto gods are manifestations of buddhas)
迹門[shakumon] first half of the Lotus Sutra, in which the Buddha appears as a spatiotemporally restricted being