Abbott-Smith Manual Greek Lexicon
νεφρός (G3510)
1 νεφρός , -οῦ, ὁ , [in LXX for כִּלְיָה , Ex 29:13 , al.; metaph., Ps 7:9 15 (16):7 25 (26):2 , Wi 1:6 , al.;] a kidney ; pl., the kidneys , reins ; metaph., of the will and affections: ν. καί καρδίαι (thoughts), Re 2:23 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain