A portmanteau of "herb" and "urban", can be pronounced with emphasis on the 'h' or more similarly like "urban".
Describes something characterized by a harmonious blending of the natural with the synthetic. For example, a person who lives happily in a city but still feels "in touch with nature" and doesn't fall apart when the internet crashes or it's time to go hiking. Could also be one who lives far away from other humans, perhaps deep in the country, but nevertheless has all the modern amenities and is comfortable with technology and modern innovation.
Dissimilar to the hippy who denounces all things man-made, and nothing like the yuppie and his ilk, who wouldn't last five minutes without a cell phone.
He's an herban trekker, you can tell by the solar-powered GPS made of recycled materials he carries but hasn't used for the last three days of this hike.