La puerta está bajo del reloj.
Bajo = Low or underneath y = and bastante = a lot; much; enough; sufficient.
This is clumsy Spanish syntax. It means "Underneath one there is [a] road." A better arrangement of the words is "abajo hay una calle." There is nothing clumsy about the arrangement. It means, "Underneath, there's a road."
It can mean different things in different contexts, but generally it means either under or down.
underneath = unterhalb
She left her bag underneath the table.
Yes, it is. Underneath, like beneath, can also be a preposition (underneath something) but can be used without an object. (e.g. He lifted the rock and looked underneath.)
stand underneath a doorframe, or underneath a table
The Underneath - band - ended in 2010.
The Underneath - band - was created in 1996.
Underneath Your Clothes was created in 2001.
I keep my shoes underneath my bed. A submarine is most effective when it is underneath the surface of the sea.