Any of a set of colored plates each containing a pattern of dots of various colors and sizes, forming a number or shape clearly visible to those with normal color vision; used in testing for color blindness.
Origin
Designed by Dr. Shinobu Ishihara at the University of Tokyo, who first published his tests in 1917.
Modern English dictionary
Explore and search massive catalog of over 900,000 word meanings.
Word of the Day
Get a curated memorable word every day.
Challenge yourself
Level up your vocabulary by setting personal goals.