Q; what does an awrah mean?
A: All-Praise is due to Allah,
‘Awrah in Arabic means a weak point along a border and the like.
In Misbaah al-Muneer it says: Everything that a person covers out of dignity or modesty is ‘awrah.
According to the fuqaha’, everything that it is haraam for a man or woman to uncover is ‘awrah.
Covering the ‘awrah, in the terminology of the fuqaha’, means covering that of which exposure is shameful and causes shame, whether the individual is male or female or hermaphrodite.
See: al-Mawsoo‘ah al-Fiqhiyyah, 24/173
Majority of Muslim scholars define that the limits of the 'Awrah' of a man is what is between navel and knee; navel and knee are not from Awrah. There are many proofs supporting their stand such as the Hadith Imams Ahmad , Abu Dawood , and al-Daruqutni reported with a good chain that the Prophet (Sallallahu Alaihi wa Sallam) said: "What is between navel and knee is Awrah" .
Imams Abu Dawood and Ibn Majah reported from Ali that the Prophet (Sallallahu Alaihi wa Sallam) said: "Do not unveil your thigh, and do not look at the thigh of the living and the dead" .
Also, Imams Ahmad and al-Tirmizi reported from Ibn Abbas that the Prophet (Sallallahu Alaihi wa Sallam) once passed by a man whose thigh was uncovered. He said to him: 'Cover your thigh, indeed thigh is (a part) of Awrah" .
Imams Malik , Ahmad , Abu Dawood and al-Tirmizi reported from Jarhad al-Aslami that the Prophet (Sallallahu Alaihi wa Sallam) passed while his thigh was uncovered, he said to him: 'Cover your thigh, it is (a part) of the Awrah" .
Covering the ‘awrah is one of the conditions of prayer being valid because Allah, may He be exalted, says: (interpretation of the meaning):
“Take your adornment (by wearing your clean clothes) while praying”
Ibn ‘Abbaas (may Allah be pleased with him) said: What is meant by adornment in this verse is wearing clothes whilst praying. This was narrated by al-Tabari in his Tafseer, 12/391
Awrahs for people who are praying fall into several categories:
(1) Minimum ‘awrah. This is the ‘awrah of a male between the ages of seven and ten; his ‘awrah is the two private parts only, front and back.
(2) Moderate ‘awrah. This is the ‘awrah of one who has reached the age of ten and above, between the navel and the knee.
(3) Maximum ‘awrah. This is the ‘awrah of an adult, free woman. All of her body is ‘awrah when praying, except for her hands and face.
And Allah knows best...