Blood is thicker than water
What's the meaning of the phrase 'Blood is thicker than water'?
By saying 'blood is thicker than water' we mean that family bonds are closer than those of outsiders.
Note: The notion that this expression originally conveyed the idea that soldiers, who shed blood together, are closer than others who don't is speculative and I can't find any evidence to support it.
What's the origin of the phrase 'Blood is thicker than water'?
The first example of the proverb 'blood is thicker than water' that I can find in print in English is in Allan Ramsay's Collected Scots Proverbs, 1737:
Blude's thicker than water.
There are claims made that an earlier form of this phrase existing in Middle German in the 12th century and appear in Heinrich der Glîchezære's epic Reinhart Fuchs, circa 1180. The English version of that text is translated as "I also hear it said, kin-blood is not spoiled by water". I don't have access to the text in question so I can't check that.
The text doesn't appear to be the same as the English 'blood is thicker than water' so, even if 'kin-blood is not spoiled by water' did exist in German in 1180, it isn't clear they are the same proverb. It is possible that the Germans coined the proverb in the 12th century and it lay dormant for 600 years before re-emerging in Scotland but that seems less than likely.
What we can say for certain is that the proverb existed in English by 1737 and that Sir Walter Scott made it available to a wider public when he included it in his hugely popular novel Guy Mannering; or the astrologer, 1815:
"Weel, blude's thicker than water; she's welcome to the cheeses and the hams just the same."
Scott harvested evocative phrases and imagery from many sources and repackaged them for his large and devoted audience.
And, just so you know, water has a viscosity of about 0.009 poise; plasma has a viscosity of about 0.015 poise so, blood is thicker than water.
See also - phrases coined by Sir Walter Scott.
See also: the List of Proverbs.