Definition from Wiktionary, the free dictionary
- Color used by New York taxicabs; taxi yellow is one of the most famous colors in the business.
taxi yellow colour:
1999, Gillian Roberts, Time and Trouble:
- “No,” Emma said, “this could be important. Not taxi yellow, so what kind of yellow did it seem?”
2002, Mac Ragan, Matchbox Car:
- The car was painted an authentic “taxi-yellow” and featured an off-white or red interior, complete with driver.
- 2002, Nancy Geary, Misfortune: A Novel 
- “I remember. The walls were taxi yellow,” she added, hoping he might smile.