From Japanese-English FreeDict Dictionary ver. 0.1:
[ichi1] [news1] [nf21] 芯 /(en)tʃˈaɪniːz(ja)lˈe̞tə/, [ichi1] [news1] [nf21] しん /ɕˈiɴ/
1. (noun (common) (futsuumeishi))
wick, marrow, staple (for stapler), (pencil) lead, stuffing, pith
2. 心・しん・1core, heart, centre, center