concrete jungle
An overcrowded, unsafe and/or crime-ridden urban environment or city, characterized by the congestion of large buildings and roads. After years living in that concrete jungle, I'm looking forward to being in a place with a bit of grass and friendly neighbors.
be cast in concrete
To be firmly or permanently established; to be unalterable or not subject to change. The healthcare law looks promising, but we'll have to wait until it's cast in concrete before we know exactly what it will do.
cast in concrete
Firmly or permanently established; not subject to change; unalterable. The healthcare law looks promising, but we'll have to wait until it's cast in concrete before we know exactly what it will do.
set (something) in concrete
To establish something firmly or permanently; to make something unalterable or not subject to change. The healthcare law looks promising, but we'll have to wait until Congress sets it in concrete before we know exactly what it will do.