Goân-chú-he̍k (Eng-gí: atomic nucleus), sī goân-chú tiong-sim nn̄g khoán hu̍t-chú (tiong-chú kap iông-chú) cho͘-ha̍p chiaⁿ-sêng ê kò͘-chō, sī goân-chú chit-liōng ti̍t-beh choân-pō͘ ê lâi-goân, chóng-sī goân-chú-he̍k chiàm kui-ê goân-chú chóng thé-chek chin chió.

Goân-chú-he̍k ê ti̍t-kèng hoān-ûi tùi chúi-sò͘ ê 1.75 fm (1.75×10−15 m) kàu tāi-iok 15 fm ê tāng goân-chú (pí-lūn uranium).