What Is Haram in Islam and What Is Halal?
Question

What is the definition of haram and halal?
Praise be to Allah.What does haram mean?
Haram is that for which the one who does it may be punished and the one who abstains from it will be rewarded, if the reason for his abstinence is following the prohibition of Allah. 
What does halal mean?
The halal is that in which there is no sin in doing it and no sin in not doing it, but if a person intends to enhance his obedience to Allah by doing it, then he will be rewarded for this intention.
Who has the right to say what is halal and what is haram?
Dictating what is halal and what is haram is the right of Allah Alone. There are people who make halal some of that which Allah has forbidden, and people who make haram some of that which Allah has permitted. 
Some people invent acts of worship which have not been prescribed by Allah and which in fact He has forbidden. The basic principle of religion is that the halal is that which Allah and His Messenger have permitted, and the haram is that which Allah and His Messenger have forbidden. 
The religion is that which Allah and His Messenger have prescribed. No one has the right to go beyond the limits of the Straight Path with which Allah sent His Messenger. Allah says (interpretation of the meaning):
“And verily, this is My straight path, so follow it, and follow not (other) paths, for they will separate you away from His path. This He has ordained for you that you may become Al-Muttaqun (the pious)” [al-An’am 6:153]
Allah mentions in Surah al-A’nam, Surah al-A’raf and elsewhere the things for which He condemns the mushrikin (polytheists, those who associate others in worship with Allah), which is that they made haram things which Allah had not forbidden, such as the bahirah and saibah (camels to which certain taboos were attached for the sake of their idols), and they permitted things which Allah had forbidden, such as killing their children, and they prescribed in their religion things that Allah had not permitted. So Allah says (interpretation of the meaning):
“Or have they partners with Allah (false gods) who have instituted for them a religion which Allah has not ordained?” [al-Shura 42:21]
These things included things that are haram in and of themselves, which they made into acts of worship, such as shirk (associating others in worship with Allah) and things which are obscene, such as performing Tawaf around the Ka`bah naked, etc.
And Allah knows best.
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