Avogadro tēng-sò͘ (Eng-bûn: Avogadro constant; L; NA) tī bu̍t-lí-ha̍k kap hòa-ha̍k ê léng-he̍k sī lia̍p-chí-sò͘ (it-poaⁿ sī goân-chú kap hun-chú) ê chi̍t-ê sò͘-liōng. Chit-ê sò͘-liōng chiū téng-î 1 mol só͘ ū-hâm ê bu̍t-chit-liōng. In-chhú, Avogadro tēng-sò͘ sī liân-chiap mol chit-liōng kap chit-liōng ê chi̍t-ê pi-lē in-chí. Avogadro tēng-sò͘ ê sò͘-ta̍t sī: 6.022140857(74)×1023 mol−1.

Amedeo Avogadro.