You may be familiar with the term liminal space? If not, this is an important concept that can't be fully described in a post- you may want to research. But very basically:
A liminal space is a threshold. The beach is a liminal space, dividing the sea and land. Midnight is a liminal "space", dividing days. A doorway is a liminal space, dividing what is on one side of the door from the other. TRANCE is a liminal space between consciousness and unconsciousness. Liminal spaces are a good way to bridge between the magical and the mundane, this world and the spirit world. In some ways it is a form of representational magic. I hope that makes sense.
A crossroads is a crossroads- literally. Where two roads intersect. For certain special instances a "Y" type/3 way crossroads is used but usually it is simply where two roads form a cross type intersection. These are very common- but finding one good for working at is a little harder. Some areas have desolate crossroads that are not frequented and are conducive to magical workings. There is much lore associated with crossroads in particular that you can read about.
But in short crossroads are a special liminal place/space that is utilized by some traditions for magical workings.
I see! Thank you for the explanation. I will do more research into that, liminal space, especially how it pertains to trancing and divination.