In last Monday's Boston Globe, arts critic Mark Feeney had an eloquent explication of the imagery in that photo (above) of hooded Miami Heat team members honoring Trayvon Martin. Looking at the history of the garment, Feeney noted that the hood has long been associated with both spirituality (St. Francis, medieval monks) and criminality:
Hoods conceal or obscure. They can disguise or seem menacing. Such terms as "hoodlum" and "hood" bespeak this tradition. In a different way, the 'hood can be a dangerous urban area, as in the 1991 film "Boyz n the Hood."I vaguely remember looking up these various hood-words, but the results, like so many other things I once knew, had evaporated. Well, maybe not the -hood of neighborhood, which is familiar from childhood, priesthood, and falsehood, and cousin to German -heit as in Freiheit, "freedom." According to the Oxford English Dictionary, this -heit was once itself a noun meaning "person, condition, quality," but was demoted to suffix status centuries ago. Still thriving, though, it "can be affixed at will to almost any word denoting a person or concrete thing, and to many adjectives, to express condition or state."
The hood on your head (or on your hoodie), on the other hand, is "ultimately the same word" as hat, says John Ayto's Dictionary of Word Origins. "Both go back to Indo-European *kadh- 'cover, protect.'" Hood comes to us via "a West Germanic derivative, *khodaz. From it are descended German hut 'hat,' Dutch hoed 'hat,' and English hood."
Hoodlum (hood for short) is the mysterious one of the trio. "The name originated in San Francisco about 1870-72,* and began to excite attention elsewhere in the U.S. about 1877, by which time its origin was lost, and many fictitious stories, concocted to account for it, were current in the newspapers," says the OED. One such story derived hoodlum from a slightly mangled reversal of the name "Muldoon"; a less far-fetched one suggests it's "perhaps from German dialect (Swabia) hudelum disorderly," as Merriam-Webster Online says.
So why do these three different hoods sometimes hang out together in a tough part of town? Etymologically speaking, it seems to be pure coincidence.
*Since antedated to (at least) 1866.