The word 'snickelway' is a rather new word that is used to refer to small alleyways and passages between closely set buildings, particularly when found en masse within a particularly elderly and ingrown section of a city.
The word was coined by author Mark W. Jones in his 1983 book, A Walk Around the Snickelways of York, and remains particularly popular in the city of York. The city has proudly adopted the word to refer to its small, closed-in pathways between buildings, generally paved in flagstones and not in any way suitable for motor traffic, as they are narrow, uneven, and occasionally interrupted by stairs.
"A Snickelway is a narrow place to walk along, leading from somewhere to somewhere else, usually in a town or city, especially in the city of York."
-- Mark W. Jones
To be more precise, a snickelway is a three-way portmanteau, combining the words 'snicket', a word used in Northern England to refer to a passageway between walls or fences, ginnel, another Northerner word, this one meaning a narrow passageway between buildings, and, of course, alleyway. Generally, the word also carries a strong overtone of picturesque and antique charm, and is much more positive than simply calling a path an alleyway.
Despite its strong ties to York and Northern England in general, the word is slowly finding its way into usage to refer to tangled yet charming warrens in other parts of the world.
Snickelway is often misspelled snickleway. This is incorrect. It is also sometimes capitalized as a proper noun, which is really only proper when referring to the Snickelways of York.