Sahih Muslim 338
Sahih Muslim · Book 3: The Book of Menstruation · The prohibition of looking at `awrah
This hadith has been narrated by Ibn Abu Fudaik and Dabbik b. 'Uthman with the same chain of transmitters and they observed:
وَحَدَّثَنِيهِ هَارُونُ بْنُ عَبْدِ اللَّهِ ، وَمُحَمَّدُ بْنُ رَافِعٍ ، قَالاَ حَدَّثَنَا ابْنُ أَبِي فُدَيْكٍ ، أَخْبَرَنَا الضَّحَّاكُ بْنُ عُثْمَانَ ، بِهَذَا الإِسْنَادِ وَقَالاَ - مَكَانَ عَوْرَةِ - عُرْيَةِ الرَّجُلِ وَعُرْيَةِ الْمَرْأَةِ .
Private parts of man are the nakedness (which is concealed).