Lêng-liōng (energy) ê khài-liām sī kóng "hoān-sè ē-tàng chō-chiâⁿ piàn-tōng ê mi̍h". Chin chē só͘-chāi lóng ēng tio̍h chit ê gí-sû; ēng tī kho-ha̍k ê sî, tēng-gī khah cheng-khak; ah nā hui-kho-ha̍k (non-scientific), ì-sù tō khah bô hiah chheng-chhó.

Sih-nà sī tiāⁿ-tiāⁿ ē-tàng khoàⁿ--tio̍h ê 1 chióng lêng-liōng choán-î.

bu̍t-lí-ha̍k, lêng-liōng sī kóng ū châi-tiāu chò kang (mechanical work). Lêng-liōng ū chin chē chióng hêng-sek, chhin-chhiūⁿ ū ūi-lêng (potential energy), ūn-tōng-lêng (kinetic energy), tiān-lêng (electrical energy), téng-téng. Ta̍k chióng hêng-sek ê tan-ūi lóng chham chò kang sio-siâng, la̍t (force) chok-iōng 1 toāⁿ kī-lî. SI ê lêng-liōng tan-ūi sī joule, tō sī 1 newton chok-iōng 1 m hn̄g.

Lêng-liōng mā hō-chò lêng-goân, e-nú-jih.