What is the meaning of the expression : 'Blue blood' ?

Correct — C, (c) An aristocrat.

‘Blue blood’ means noble or aristocratic ancestry, and by extension a person who has it — an aristocrat. That is the sense dictionaries record, and it is the only sense the phrase carries in ordinary English.

The expression is a translation of the Spanish ‘sangre azul’. In medieval Castile the old aristocratic families claimed descent untouched by Moorish or other foreign marriage, and the outward sign appealed to was complexion: on a fair skin that had never been darkened by working in the sun, the veins show through as blue. The nobility could point to the blue tracery on their forearms; the labouring poor, tanned by the fields, could not. The claim is nonsense as biology — all human venous blood is red, and looks blue only because of how skin scatters light — but the phrase it produced entered French as ‘sang bleu’ and English as ‘blue blood’, and there it has stayed.

So the option to look for is the one about birth and rank, not the one about colour, and not the one about value. That is the discipline the item is really testing. Three of the four options are built by taking the words at face value: a blue liquid must be dyed water, or sap, or something rare and therefore expensive. Only ‘An aristocrat’ answers the phrase as a phrase. Note also the grammar of the options — the stem asks for the meaning of the expression, and the keyed option is a person, which is how ‘blue blood’ is most often used in a sentence: ‘the guest list was full of blue bloods.’

Why the others are wrong

• (a)Polluted industrial waste water — ‘Polluted industrial waste water’ is the option for a candidate who reasons from the colour. Effluent from a dye works or a chemical plant can indeed run blue, and the phrase ‘blue blood’ might be coined tomorrow by a newspaper to describe a poisoned river; but it has not been, and an idiom means what usage has settled on, not what it could plausibly have meant. There is no established English expression in which ‘blue blood’ names pollution. The option is also a reminder of a habit worth resisting in a vocabulary paper: importing a technical or topical frame — here, environmental reporting — into a phrase that belongs to social description. If the item wanted effluent, the idioms available are quite different, and none of them involves blood.
• (b)Sap of teak wood — ‘Sap of teak wood’ works the same trick from a different direction: it invites you to think of ‘blood’ as the fluid inside a living thing, and of a tree as a living thing with fluid inside it. English does sometimes speak of the sap of a plant in blood-like terms, and Indian usage knows the reddish exudate of some trees. But no dictionary records ‘blue blood’ as a term in forestry or botany, and teak sap has no claim on the phrase. The wrong step here is a real one and worth naming: extending a metaphor by analogy, rather than recalling the fixed expression. Idioms do not generalise. ‘Blue blood’ is about human descent, and the moment the phrase is used of a tree it stops being that idiom and becomes an invention.
• (d)A costly object — ‘A costly object’ is the near miss on this list, because it is close to a real English idiom — but a different one. The phrase that carries value is ‘blue chip’, from the highest-value counter at the gaming table, which in the language of the stock market names the shares of large, sound and expensive companies. ‘Blue riband’ likewise marks the highest distinction in a field. Neither is ‘blue blood’, which says nothing about price and everything about pedigree. It is possible for the two to overlap in the world — aristocrats are often rich — but a vocabulary item asks what the words mean, not what tends to be true of the people they describe. A blue blood who has lost his fortune is still a blue blood.

Colour words carry a great deal of idiomatic freight in English, and ‘blue’ carries more than most. ‘Blue blood’ is aristocratic descent; ‘blue chip’ is high value and safety; ‘blue-collar’ is manual work, from the colour of a workman’s shirt; ‘bluestocking’ was once a learned woman; ‘out of the blue’ means without warning; ‘once in a blue moon’ means very rarely; ‘a blue-eyed boy’ is a favourite; ‘to feel blue’ is to be sad; and a government ‘blue book’ is an official report.

What makes the family worth learning as a family is that its members share nothing but the colour. Knowing that ‘blue’ often signals something about rank or worth will not tell you which idiom you are looking at, so each must be learned whole, with its meaning attached.

‘Blue blood’ also illustrates how idioms travel between languages. It is a loan-translation, or calque, of the Spanish ‘sangre azul’: the words were translated one by one and the phrase carried its meaning across intact. English is full of these — ‘it goes without saying’ from the French ‘cela va sans dire’, ‘lose face’ from Chinese, ‘long time no see’ from a similar route. A calque is worth spotting because its literal meaning in English is often odd, which is exactly the property an examiner uses to build wrong options.

Key facts

• ‘Blue blood’ means noble or aristocratic ancestry, and is also used of the person who has it — an aristocrat.
• The phrase is a loan-translation of the Spanish ‘sangre azul’, which passed into French as ‘sang bleu’ and then into English.
• The image behind it is complexion: veins show blue through fair skin that has not been darkened by outdoor labour. As biology it is baseless — human blood is red.
• ‘Blue chip’, not ‘blue blood’, is the expression that carries the sense of high value: it comes from the highest-value counter in a game and now describes shares in large, sound companies.
• Other members of the ‘blue’ family: blue-collar work, a blue-eyed boy, out of the blue, once in a blue moon, to feel blue, a government blue book.

Common traps

• Reasoning from the colour to a liquid — dye, effluent, sap. Every one of those readings takes the words apart, which is exactly what an idiom forbids.
• Confusing ‘blue blood’ with ‘blue chip’. One is about pedigree, the other about value, and the option list here offers the value reading.
• Assuming that because aristocrats are usually wealthy, an option about costliness will do. The item asks what the words mean, not what is often true of the people.
• Expecting the keyed option to be a definition of the same grammatical shape as the stem. Here the stem asks for a meaning and the answer is a person.

• practice — not a real PYQ

  What is the meaning of the expression : ‘a blue-chip company’ ?

  • (a)A company owned by an aristocratic family
  • (b)A large, financially sound company whose shares are considered safe
  • (c)A company that manufactures semiconductors
  • (d)A newly listed company

  Answer(b) A large, financially sound company whose shares are considered safe — the phrase comes from the highest-value counter used in gaming, and in market usage it describes established companies with a long record. Option (a) is the confusion with ‘blue blood’, option (c) reads ‘chip’ literally as a piece of silicon, and option (d) describes the opposite of what the phrase claims.

• practice — not a real PYQ

  ‘The news of his resignation came out of the blue’ means that the news

  • (a)was expected for months
  • (b)arrived without any warning
  • (c)was published in an official report
  • (d)made everybody sad

  Answer(b) arrived without any warning — ‘out of the blue’ pictures something falling from a clear sky. Option (c) mixes it with the government ‘blue book’, option (d) with ‘feeling blue’, and option (a) states the reverse of the idiom’s meaning.