Yellow color - Colloquial Expressions

• In railway signaling, yellow is often the color for warning, slow down, such as with distant signals.
• The Yellow Pages is the section of a phone book or online phone directory that lists business numbers by category. They are named for the color paper they are printed on in phone books to distinguish them from the regular listings.
• Yellowcake (also known as urania and uranic oxide) is concentrated uranium oxide, obtained through the milling of uranium ore. Yellowcake is used in the preparation of fuel for nuclear reactors and in uranium enrichment, one of the essential steps for creating nuclear weapons.
• The Yellow Rose of Texas, or "Harison's Yellow", first bloomed in New York City in the 1830s.
• Yellow is the color of the snooker ball which has a two-point value.
• Yellow could be the color of an old jeep.
• When yellow is mixed with green, it creates Lime
• In China, a "yellow movie" is pornography; contrast "blue movie".
• There is a yellow smile, in Arab culture, which is an ingenuine smile. A yellow smile is used when a person is concealing lack of interest, fear, or any emotion he wishes to keep hidden. It is sometimes used as a joke, by making a face of a crooked, ingenuine smile, when somebody tells a bad joke or is trying to make others laugh for something they do not find humorous enough.
• There is also a French expression "rire jaune" ("yellow laughter") which could be translated into English as "mirthless laughter", laughing without mirth, laughing when you don't find the joke funny, or when the joke is directed at you.
• "Yellow" is also mid-twentieth-century American drug slang for Nembutol, a barbiturate. This is due to the yellow color of the pills.