Yellow tulip

Crystal ball yellow

Yellow - Color symbolism and psychology

Sunlight, joy, happiness, earth, optimism, intelligence, idealism, wealth (gold), summer, hope, air, liberalism, cowardice, illness (quarantine), hazards, dishonesty, avarice, weakness, greed, femininity, gladness, sociability, summer, friendship, Gemini, Taurus, Leo (golden yellow, star signs), April, September, deceit, hazard signs, death (Middle Ages), mourning (Egypt), courage (Japan). Yellow ribbons were worn during times of warfare as a sign of hope as women waited from their men to return.
During the Middle Ages, both green and yellow were used to symbolize the devil.
Color symbolism and psychology - Wikipedia, the free encyclopedia

Yellow is a color

Yellow is the color evoked by light that stimulates both the L and M (long- and medium-wavelength) cone cells of the retina about equally, but does not significantly stimulate the S (short-wavelength) cone cells; that is, light with lots of red and green but not much blue. Light with a wavelength of 560–580 nm is a yellow, as is light with a suitable mixture of somewhat longer and shorter wavelengths.
Yellow - Wikipedia, the free encyclopedia