Green Light
WordNet
noun
(1) Permission to proceed with a project or to take action
"The gave the green light for construction to begin"
(2) A signal to proceed
WiktionaryText
Etymology
From the standard red-green color scheme used in traffic lights and railway signals.
Noun
- A traffic light in its green state (indicating that vehicles may proceed).
- The drive home was much faster than usual; somehow we managed to hit every green light.
- approval, or permission to proceed.
- We have a green light on the project. Work starts today.