In Arabic, and Islam, term with at least 3 meanings, meanings that are conflicted and linked at the same time.
Haram can mean 'forbidden', something negative to be rejected and avoided. It can mean 'sacred', something that outsiders may not enter. And it can designate the private parts of a home; from this comes the famed harem, the community of royal concubines, f.x. of the Ottoman sultan.
The conflict between what is forbidden and what is sacred is explained by
Holy site (haram)
Two sites in the Muslim world are commonly designated by the term 'haram', Mecca and Madina. In modern times, the construction of Jerusalem being the 3rd most holy place of Islam, has made many claim it also to be a place of haram (see Mi'raj).
The great mosque of Mecca is called al-masjid al-haram.
Many haram zones are defined not to allow entry for non-Muslims. The whole cities of Mecca and Madina er off limits for non-Muslims.
The term 'haram' used for what is illegal is the opposite term to halal, what is legal. Definitions of the two categories are linked, what halal is defined in Sharia, Muslim law, as everything that is not illegal, and the things illegal are haram.
The term haram is a very common term in everyday language of Muslims, expressing things that are not defined as illegal, but what people consider non-Muslim. In particular in the face of modernity, it is very common to reject things simply by calling them haram. In this sense, haram is used in stead of the older term, bid'a, illegal invention.
Female section of the home (harīm)
The third meaning is for the part of a Muslim house set apart for the women.