Usually , we talk about words and phrases that Americans use without even thinking much about them . But , of course , anybody can make up a phrase and give it meaning . By the way , there's actually a phrase for this act : to coin a phrase means to invent a new saying . The Grammarist website explains that using the word “coin ” as a verb began in the 1300s . It related to putting an image on a piece of metal money . But the expression did not come about until 500 years later , when some English speaker coined the phrase “to coin a phrase .” Anyway , today we begin with a phrase that scientist Wallace Nichols coined in more recent years . It explains how people feel when they are near water . That phrase is “blue mind .” It is also the name of Wallace's book , published in 2014 . He uses the phrase to mean a sense of calm and happiness one has near a lake , river , ocean or other body of water . In this phrase , the color blue is positive . It suggests both the color of water and a feeling of mental quiet . The color blue is also sometimes linked to a feeling of security , say researchers who study how colors make people feel . If you call someone true blue , you mean you can depend on her completely . A true blue friend is loyal and trustworthy . A friend like that is extremely valuable . You might even say that someone who is true blue is worth her weight in gold . But that would be mixing idioms ! In some phrases , blue relates to being the best . If you win top prize , you win a blue ribbon . Sometimes you really do get a piece of fabric that is the color blue . But you can also just describe something that is excellent with the adjective “blue ribbon ” – such as a “blue ribbon restaurant .” In business , a successful company that has a very positive public image can be called a blue chip operation . Anything that is of high quality can be blue chip . A writer on the business website Motley Fool reports that English speakers started using the term in the early 1900s . It relates to the game of poker . In the game , people use flat , round pieces called chips . The blue chips had the highest value . At the end of the game , players exchanged their chips for real money . So it is no surprise that the more blue chips you gain , the better ! But in some other English expressions , the word "blue " is linked to some more complex ideas . If you have the blues , you are sad , even depressed . The website Word Histories says that this sorrowful meaning appeared in a story in England in the 1400s . The color blue related to skin that was hurt or bruised . Artists may also go through a blue period . This is a time when their work suggests painful feelings . Hopefully , those low times do not come very often – perhaps once in a blue moon . This expression has come to mean happening rarely . It refers to the unusual times when one month includes two full moons . The second moon is a “blue moon .” Such an event is seen as special and noteworthy . In comparison , something that is a bolt from the blue is unexpected and usually bad . Let's say you and your business partner had just launched a new store . You thought you were working well together . So , the news that she was leaving to take a new job was a bolt from the blue . The idea is that of lightening or thunder appearing in a cloudless sky . News of unexpected illness or a sudden death can also be a bolt from the blue . So , what does the color blue mean for you ? Calmness , loyalty , sadness , surprise or something else ? After all , every culture and every person reacts to colors differently .