As far as I know, I coined this word. It is a noun. It is a term used to describe a location (usually man-made) frequently visited by the same people, often used as a place of social gathering. It is the merging (sort of) of habitué + terrarium. It has sad connotations, because the people who are in the habituarium, are separated from the rest of the world, not by bars or glass, but by fate or time and probably even bad decisions along the way. An example sentence would be. "As I entered the gas station, I saw the sad-faced gentlemen seated in their habituarium, staring at me from across the decades." I think it's a great word, and would like it to be used.