Glossary

Understand the terms

  • Ageusia: a dysfunction of true taste. A person with this condition cannot perceive sweet, salty, sour, bitter or umami.  
  • Anosmia: the inability to perceive odour – in other words, the loss of the sense of smell. Anosmia may be temporary, but some forms can be permanent. A person with smell loss is called anosmic. 
  • Cacosmia: an extreme form of parosmia in which smells take on a persistent and extremely unpleasant quality, often like sewage. This can be a very distressing condition.  
  • CRS: Chronic rhinosinusitis. This occurs when the nasal passages and paranasal sinuses cavities become inflamed and swollen for at least 12 weeks, despite treatment attempts. It can cause you to lose your sense of smell. If it’s caused by polyps, it’s known as chronic rhinosinusitis with polyps (CRSwP). If not, it’s known as chronic rhinosinusitis without polyps (CRSsP). 
  • Dysgeusia: a distortion of the sense of taste.  
  • ENT: the branch of medicine concerned with the ear, nose and throat. 
  • Flavour: the combination of smell and true taste. 
  • Gustation: the sense of true taste (sweet, salty, sour, bitter and umami). 
  • Hyposmia: a reduced sense of smell. A person with hyposmia is called hyposmic.  
  • Idiopathic smell loss: loss of smell that has no obvious source.
  • Mindfulness: the psychological process of bringing one’s attention to experiences occurring in the present moment, which can be developed through the practice of meditation and other training. 
  • Mouthfeel: the way food or drink feels in the mouth, rather than its taste. 
  • Nasal polyps: soft, painless, non-cancerous growths on the lining of the nasal passages or sinuses. They result from chronic inflammation due to asthma, recurring infection, allergies, drug sensitivity or certain immune disorders. 
  • Nasal rinsing: The use of a saltwater rinse, sometimes with added bicarbonate of soda, to remove allergens and irritants. Please consult your doctor to find out if this is the right thing for you.  
  • Normosmic: person with a healthy sense of smell. 
  • Olfaction: the chemical process that forms our sense of smell. 
  • Olfactory epithelium: the specialised tissue in the nasal cavity for smell. It reacts with volatile molecules (odorants). 
  • Olfactory nerve: this runs from the olfactory cleft at the top of the nasal cavity to the olfactory bulb in the brain. It relays the signals which help us decode smells. 
  • Orthonasal olfaction: the process of sniffing. Odorant molecules go from the object up through the nostrils. Also see retro-nasal olfaction. For more information, see blog post: Two ways to smell.
  • Parosmia: a distortion in the sense of smell. For instance, the smell of coffee might become disagreeable and have an off, burned smell. Parosmic distortions can be hard to describe, but most often are described as smoky or burned. A person with parosmia is called parosmic.  
  • Phantosmia: a disturbance in which the person perceives smells that do not exist (smell phantoms). These smells are not associated with a smell that is present. A person with phantosmia is called phantosmic.  
  • Polyps: see nasal polyps 
  • Post-nasal drip: this occurs when excess mucus accumulates and descends from the nose to the back of the throat.  
  • Post-viral anosmia: smell loss after a cold, virus or sinus infection. 
  • Retronasal olfaction: Perception of odour in the mouth. When a mouthful of food is chewed, odorant molecules are released in the mouth cavity. During swallowing, some of these molecules escape up into the nose from the back of the throat. The combination of retro-nasal olfaction and true taste creates flavour. For more information, see blog post: Two ways to smell.
  • Rhinology: the branch of medicine concerned with conditions of the nose. 
  • Smell training: a supportive therapeutic technique to stimulate the sense of smell and encourage regeneration of the olfactory nerve. Read more about the benefits. 
  • Sniffin’ Sticks test: a test, administered in a clinic, that scores a patient on threshold, discrimination and identification of smells (TDI score).  
  • Steroids: steroids are drugs used to relieve swelling and inflammation. They can be taken systemically (as tablets) or applied locally (as a spray or drops). 
  • Trigeminal nerve: this cranial nerve provides sensation to the face. Through it we experience the tingly sensation of menthol or the burn of chillis. A trigeminal reaction is often considered a taste or smell but in fact it’s a response by this nerve.  
  • TBI: traumatic brain injury. A blow to the head can cause the olfactory nerve to be stretched, bruised or sheared off, resulting in changes, or loss, of smell. 
  • True taste (gustation): this refers to the experience of the tongue: sweet, salty, sour, bitter and umami (savoury). These true tastes are interpreted by receptors on the tongue and in the mouth. When someone says, “This tastes good”, they probably mean that it has good flavour. Flavour is the combination of true taste and smell that is experienced through retro-nasal olfaction. 
  • Umami: one of the five basic tastes. Umami has a savoury taste that comes from a naturally occurring substance called glutamates. There is umami in mushrooms, certain kinds of hard cheeses, meats, soy sauce and other savoury foods.  
  • UPSIT test: University of Pennsylvania Smell Identification Test. A scratch and sniff test that tests a person’s ability to identify common smells.