The thobe is a
Saudi name for the traditional
Middle-Eastern loose, long-sleeved, ankle-length
shirt/
robe which one pulls over the head to put on. (Various regions also have other names for the garment, such as "
dishdasha," or
jellabiyyah/
djellaba.) Traditionally, the
men's thobe is fairly plain,
white in summer and darker colors in the winter, and made of
linen or
wool, though
cotton and
polyester blends are common now. (Martha Kirk's book
Green Sands says modern men wear
shorts underneath in summer;
sirwal pants are more traditional. The Desert Boutique online store even sells
long underwear which look just like those worn by Westerners to me.) Thobes often have
pockets and can have various types of
collars and
cuffs.
Women's thobes are often heavily embroidered and made of more colorful fabrics; they can be sheer because the thobe is only an outer layer worn over a dara’a (a straight-cut dress) with sirwal pants below that. Women's prayer thobes are hooded, unlike the more everyday ones, and have hand slits rather than sleeves; prayer thobes are not intended to be worn outside. However, women's everyday thobes are covered with the abaya cloak when they leave their homes.
Sources:
Martha Kirk, Green Sands: My Five Years In The Saudi Desert, Lubbock, Texas: Texas Tech University Press, 1994.
http://www.saudinf.com/main/q031.htm
http://www.alhannah.com/index2.html
http://www.quickbizsites.com/desertboutique/home
http://www.arab.net/saudi/culture/sa_clothing.html
http://www.kfshrc.edu.sa/arabian/html/arabic_dress.html
http://www.ecssr.ac.ae/Land/costum.html
http://www.saudiembassy.net/publications/Magazine-Summer-01/Dress.htm