A few days ago I found myself looking at the Moon, as one does.  It wasn’t full enough to be worth howling at but it was nearly there, and it put me in mind of three similar words of which I am quite fond.  They are gibbous, glabrous and glaucous.


I had been looking at a waxing gibbous moon.  To wax means to increase or grow, though when I conducted a Google search just now on waxing one of the first hits was “Top 10 places for a Brazilian wax in Florence”; I do wonder sometimes what data Google are keeping on me, though it did remind me of a rather charming sign I once saw outside a barber’s shop in Locorotondo, Puglia.

When applied to the Moon, gibbous means unequally convex.  I was taught at medical school that the word comes from gibbet, which Samuel Johnson in his Dictionary of the English Language rather charmingly defines as:

A gallows; the post on which malefactors are hanged; or on which their carcasses are exposed.

He also gives some examples of usage:

When was there ever cursed atheist brought

Upon the gibbet, but he did adore

That blessed pow’r which he had set at nought?

Davies (according to Johnson, though I don’t know which Davies he meant)

The consultant who was teaching us claimed that traditionally the most auspicious time to hang criminals was when the Moon was neither full nor half, and hence it was referred to as gibbous.  He seemed convinced but I haven’t been able to find any evidence that this was other than apocryphal.  Indeed, it seems that gibbous comes from the Latin word gibbus, meaning a bulge or lump.  The term gibbus is used medically to refer to the swelling arising from an angulation of the spine due to a dislocated, fractured or collapsed vertebra, as happens during hanging (assuming that the hangman does a proper job of ensuring the rope is the correct length to result in a broken neck; too short and death is excessively slow from asphyxiation; too long and the head is pulled off).  As an oncologist I used to encounter a gibbus from time to time when a vertebral body had been destroyed by cancer and collapsed; it was usually accompanied by paralysis due to spinal cord compression.

Note that the past tense of hang is hanged, not hung, when referring to execution.  You might like your meat hung (it would be rather tough and tasteless otherwise) but that is victuals, not villains.

Gibbous, when applied to non-celestial bodies, can also simply mean bulging, like the eyes of somebody with Graves’ disease, an autoimmune condition with antibodies produced against the thyroid gland, which stimulate rather than destroy it, leading to thyrotoxicosis and all that goes with it (including eyelid retraction); the antibodies also cross-react with the eye muscles, causing them to swell and push the eyeballs out of their sockets (contrast this with Hashimoto’s disease, where antibodies damage the thyroid leading to thyroid insufficiency, with no effect on the eyes, and any tissue swelling being generalised – myxoedema).  The comedian Marty Feldman was famous for his odd appearance due to Graves’ disease.  The thyrotoxicosis is straightforward to treat, and one way to do this is with radioactive iodine-131.  The eye changes are rather harder, though radiotherapy to the orbit can be helpful here.

Gibbet comes from the French gibet, which means a gallows but also a bent stick or club, so possibly also from Latin Gibbus, since such a club would bulge.  Maurice Ravel wrote a beautiful and evocative piano piece, Gaspard de la Nuit with the middle movement entitled Le Gibet painting a haunting musical picture of a corpse swinging from a gallows by moonlight.  There is a rather good performance of this by David Bowie in his film The Man who Fell to Earth.


This means smooth, or in particular hairless. It comes from the Latin glaber, which has more-or-less the same meaning. The spot between the eyebrows is known anatomically as the glabrum. Nowadays if the glabrum isn’t properly glabrous people call it a monobrow (or unibrow if you prefer; I prefer neither since mono is from Greek, uni is from Latin and brow is Germanic, so they don’t sit very comfortably together; in any case the correct medical term is synophrys from the Greek σύνοφρυς “with meeting eyebrows”).

The Mexican painter, Frida Kahlo de Rivera, had a rather striking synophrys, which appears in her many self-portraits.  It is usually a normal variation, but can be pathological, for instance in fetal alcohol syndrome (due to heavy drinking during pregnancy) or Cornelia de Lange syndrome (a genetic disorder characterised by multiple developmental abnormalities, including elongation of the philtrum).

Ah yes, philtrum. This is the hollow between the nose and the upper lip. It is the place where you should place a drop of love philtre (potion) while your intended is sleeping in the hope that they will fall hopelessly in love with you. You have to ensure that they see you first on awakening, and not, for instance, a weaver who happens to have been magically transformed into a donkey. This works quite well in ducks and geese, where indeed no philtre is required at all – the ducklings / goslings will simply follow the first large moving object they see when they hatch, as famously demonstrated by Konrad Lorenz.

Every bump and hollow in the body has a name.  Sometimes it is simply a description of what it does, such as the muscle known as the corrugator cutis ani (look it up).  Sometimes it is named after the doctor who first described it, such as the Eustachian canal, the canal of Schlemm, the canal of Nuche, the bursa of Fabricius and the retroperitoneal organ of Zuckerkandl.  When I was an undergraduate at Cambridge, someone with a voice like John Major sidled up to me at a party and started a conversation by asking “Did you know, there is no scientific name for the back of the knees?” “Yes there is, I replied, it is called the popliteal fossa.” “Oh” he replied, and wandered off to annoy somebody else with “Did you know, Beethoven was a terrible dancer?”.


This is from the Greek word Γλαῦκος, meaning the colour of the sea.  I am told that the ancient Greeks didn’t have names for colours, and would refer to objects according to what they ressembled.  So they might say “frog-coloured” instead of green (I don’t know what colour the frogs are in Greece, but maybe there was a convention that they are supposed to be green).  I don’t know if this really was true, though there are very few references to colour in Greek literature.  This has led to speculation that colour vision was not fully developed in Homeric times, which is nonsense.  However, there does seem to be evidence that when civilisations name colours, they start with light and dark, adding red at the next stage of development, then green or yellow, with blue coming last of all.  Indeed, it is only comparatively recently that it has occurred to anybody to name the colour of the sky at all.

Glaucous, however, doesn’t refer to the deep inviting blue of the Aegean.  It is more a sort of greyish-green.  It is used by poets and biologists.  I have a Rosa glaucosa in my garden, which has lovely grey-green foliage and small pink flowers, though just at the moment it is covered in them and looks quite striking.

Glaucous is also the colour that the eye will end up if raised intraocular pressure is left untreated and is allowed to progress to blindness.  Hence the name of this condition – glaucoma.  At Westminster Medical School I was taught by the ophthalmologist Patrick Trevor-Roper (brother of the historian Hugh, later Lord Dacre, who awarded me my degree and once lent my father a pair of socks while travelling in India as a young man; he never returned them) that a reliable way to diagnose death was from the loss of turgor due to a rapid fall in intraocular pressure.  Perhaps it is unusual for an eye surgeon to examine any other part of the body, but personally I prefer to listen for heart sounds and breathing.

Turgid is another nice word.  Swollen and congested, nowadays often applied to badly-written prose.  Medically, turgor refers to the state of turgidity and tension in cells or tissue.  Skin turgor can rapidly give you an idea of whether somebody is dehydrated – just pinch a fold of skin over the back of the hand, or squeeze together some of the skin on the forehead, and see whether it springs back as soon as you let go or takes a few seconds.

When I was learning about osmosis at school my biology teacher took us through an experiment involving pieces of raw potato which we left soaking in fresh and in salty water for half an hour and then assessing how their turgidity had changed.

The opposite of turgid, of course, is flaccid, pronounced “flaxid” and not “flassid” as some are wont to do. Or maybe they do it assidentally.

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