Like many religions, Islam commands its followers to dress "modestly", and as a result, various items of clothing have developed that are now considered emblematic of Islam. There is often a great deal of confusion among non-Muslims—and even Muslims!—regarding these, as the wide variation in Muslim cultures has resulted in a similarly varied number of interpretations of both what must be covered to be modest and how to do so. Before we begin, we should note that Islam requires modesty of both men and women; it's simply that the requirements for men are rather more clear-cut and a bit more revealing than requirements for women. Men are required to cover at least everything "from navel to knee"; shorts are therefore technically banned. Most Muslim societies tend to frown on men going bare-chested in public, as well. For example, some particularly fervent Muslim men opt to play sports wearing tracksuits. Furthermore, many men see it as sunnah (commendable tradition of The Prophet Muhammad) to wear some kind of head covering; this usually takes the form of a kind of skullcap called a taqiya which looks rather like a large yarmulke. That said, it is true that the rules for women are rather more restrictive. Consensus among traditionalist clerics is that Muslim women must, while in public and while praying, cover their whole body except for the hands and the face. Some clerics are of the opinion that the hands and face except the eyes must be covered; others are of the opinion that feet up to the ankle can be shown (a relief in many Muslim countries where some poor folk cannot afford shoes). More liberal/reformist muftis are of the opinion that modesty must be determined relative to the society and can change over time; thus, in some countries, liberal but observant women might not wear a head covering in most situations, but carry one around for prayer and entering mosques (it is undisputed that Muslim women must cover their hair while praying; Jewish doctrine is much the same, Catholicism required this well into the 20th century, and this remains a requirement in Orthodox Christianity). And of course, Islam can be quite a personal religion; theoretically, anyone can interpret The Qur'an and other religious texts for him or herself. And finally, we'd be remiss in not mentioning: these garments are really good for disguising your appearance. Even ordinary headscarves can make you look unrecognizable, so naturally there's a lot of room for making that look as good as possible. The result of this is a bewildering array of variations on the theme, causing confusion for many. The most common ones are what follow:
HijabThe hijab is, in theory, the generic word for "modest dress" in Islam. Indeed,in the Qur'an, the term applies to modest dress for men as well as women; the Qur'anic term for a head covering for women is jilbab. However, over time, Muslims have come to use the word hijab to mean a head-covering. It can generically mean any old head covering, including all of the ones listed below; most commonly, however, the word is used to mean a relatively simple scarf that leaves the whole face uncovered. There are hundreds of ways to wrap and fasten these around the head, with the result that a woman's hijab can be very personalized indeed: loosely wrapped, tightly wrapped, showing a bit of hair, stuffed with starched fabric, and so on. These have drawn criticism from conservative clerics on the ground that the decoration is immodest and therefore defeats the purpose of the exercise. The same criticism is, oddly, often levied by Muslim feminists who want to ditch the hijab altogether. The same odd alliance also critiques the fairly common practice among young Muslims in the West and among the rising middle classes of the Muslim world of wearing this sort of hijab with clothes that technically fulfill the requirement of covering everything while still being quite revealing (e.g. skinny jeans and tight long-sleeved T-shirts). As you might have guessed, this is the least conservative sort of hijab in most communities, asides from some old-fashioned ones that look like ordinary if floppy women's hats and for the most part went out of style decades ago.
KhimarA slightly more old-fashioned and conservative sort of hijab, consisting of a square or circular piece of cloth with a hole in the middle for the woman's face, leaving it (again) totally uncovered, but with cloth nearly to the navel in some cases. Usually light-colored.
ChadorAn Iran-specific version of the khimar, with the difference of being much larger and usually black. It reaches all the way to the ground, and thus fulfills the Iranian government's modesty requirement; however, it is not required by law as is often stated in foreign media.
AbayaNot a head covering, but rather a loose-fitting, ankle-length sleeved robe, usually paired with a head covering. Most common in Arab countries; it is more or less required by law in Saudi Arabia. It is not restricted to women; while the styles of abaya are different for men and women, they are considered to be the same kind of garment and have the same name.
JilbabA variant of the hijab usually worn by South-East Asian Muslims. Some of them are long-flowing, but usually refers to quick and practical headscarf one can simply throw on the head if one needs to answer the door, say. They're not usually too garishly decorated, but some styles of Jilbab has made inroads with the Muslim fashion industry.
ManteauA Western-inspired garment (the word is French) that fulfills the requirements for hijab, other than the head. It's just a long overcoat that conceals the legs and covers the arms. A headscarf and manteau is liberal public dress for women in Iran; they are also common among observant Syrian women.
NiqabA veil for the face, covering everything below the eyes, connected to a headscarf in various different ways. These are controversial even among relatively conservative Muslims, as the idea that women's faces must be covered is not particularly widespread. They are actually banned in some Muslim countries as a threat to public safety (not being able to see the face is a serious problem, after all), and one leading religious university, Egypt's Al-Azhar, actually banned them on campus, mostly for security reasons but also on the grounds that they were (get this) of dubious Islamicity. On the other hand, the Saudi religious police are known to harass women who do not cover their faces, even though it is technically legal. They have also caused problems for Muslims in the West; a woman in America who tried to get her driver's license photo while wearing one was denied for obvious reasons, and France, citing both cultural and security concerns, banned them entirely. The Niqab is only slightly more widespread in the Gulf, and they are more closely associated with traditional-leaning women.
BurkaOr burqa or burkha.... Traditionally associated with Afghanistan, this garment is much like a chador, but rather than leaving the face clear, it covers the whole face, leaving a net or mesh of cloth around the eyes so the woman can see. This is by far the most conservative garment of the bunch, and one of the most controversialnote ; several Muslim countries have banned it in schools or even outright. It is also banned in France, as a result of banning anything that wholly conceals one's face.