liōng-chú bu̍t-lí-ha̍k kap lia̍p-chú bu̍t-lí-ha̍k, spinki-pún lia̍p-chú, ho̍k-ha̍p lia̍p-chú (hadron), kap goân-chú-hu̍t só͘ kōaⁿ ê chi̍t chióng lāi-chāi ê kak-ūn-tōng-liōng (角運動量). Spin chit ê sû sī túi Eng-gí ê "spin" ti̍t-chiap chioh--lâi, ì-sù sī "îⁿ-îⁿ-gô".

Spin sī liōng-chú le̍k-ha̍k tiong nn̄g chióng kak-ūn-tōng-liōng ê sī kî-tiong chi it, só͘-í ū-sî choân-chheng spin kak-ūn-tōng-liōng, lēng-gōa chi̍t-ê sī kúi-tō kak-ūn-tōng-liōng (軌道角運動量). Kúi-tō kak-ūn-tōng-liōng operator tiō siong-tong î kó͘-tián le̍k-ha̍k tiong mi̍h-kiāⁿ teh tńg-se̍h ê kak-ūn-tōng-liōng; po-hâm-sò͘ tī khong-kan tiong sûi kak-tō͘ piàn-hòa ê sî, kúi-tō kak-ūn-tōng-liōng tiō ē chhut-hiān. M̄-kò spin bô-kâng, i bô tāi-piáu lia̍p-chú si̍t-chè tī khong-kan tiong ū teh tńg-se̍h, kán-ná Tē-kiû teh chū-choán ia̍h-sī kan-lo̍k teh gô. Spin sī lia̍p-chú pún-sin só͘ kū-pī--ê, kap i ê tiān-hō, chit-liōng sio-kāng.

Tiān-chú ê spin kak-ūn-tōng-liōng ê chûn-chāi sī iû si̍t-giām thui-lūn--chhut-lâi, chhiūⁿ-kóng Stern–Gerlach si̍t-giām. M̄-kò che mā ē-sái iû lí-lūn thui-lūn--chhut-lâi, phì-lūn-kóng spin thóng-kè tēng-lí ia̍h-sī Pauli bô-chò-hóe goân-lí (Pauli 無做伙原理).

Ū chi̍t-kóa lia̍p-chú, chhiūⁿ photon, in ê spin tī sò͘-ha̍k siōng ē-tàng iōng hiòng-liōng lâi piáu-ta̍t. Kî-tha ê lia̍p-chú, chhiūⁿ tiān-chú, in ê spin ài iōng spinor ia̍h-sī bispinor lâi piáu-ta̍t.