Anidiosyncrasy is a unique feature of something. The term is often used to express peculiarity.[1][2]
The term "idiosyncrasy" originates fromGreekἰδιοσυγκρασίαidiosynkrasía, "a peculiar temperament, habit of body"[3] (fromἴδιοςidios, "one's own",σύνsyn, "with" andκρᾶσιςkrasis, "blend ofthe four humors" (temperament) or literally "particular mingling".[citation needed]
Idiosyncrasy is sometimes used as a synonym foreccentricity, as these terms "are not always clearly distinguished when they denote an act, a practice, or a characteristic that impresses the observer as strange or singular."[4] Eccentricity, however, "emphasizes the idea of divergence from the usual or customary; idiosyncrasy implies a following of one's particular temperament or bent especially in trait, trick, or habit; the former often suggests mental aberration, the latter, strong individuality and independence of action".[4]
The term can also be applied tosymbols or words.Idiosyncratic symbols mean one thing for a particular person, as a blade could meanwar, but to someone else, it could symbolize asurgery.[citation needed]
Inphonology, anidiosyncratic property contrasts with asystematic regularity. While systematic regularities in the sound system of a language are useful for identifying phonological rules during analysis of the forms morphemes can take, idiosyncratic properties are those whose occurrence is not determined by those rules. For example, the fact that the English wordcab starts with the sound /k/ is an idiosyncratic property; on the other hand that its vowel is longer than in the English wordcap is a systematic regularity, as it arises from the fact that the final consonant is voiced rather than voiceless.[5]
Idiosyncrasy defined the way physicians conceiveddiseases in the 19th century. They considered each disease as a unique condition, related to each patient. This understanding began to change in the 1870s, when discoveries made by researchers inEurope permitted the advent of a "scientific medicine", a precursor to theevidence-based medicine that is the standard of practice today.[citation needed]
The termidiosyncratic drug reaction denotes an aberrant or bizarre reaction orhypersensitivity to a substance, without connection to thepharmacology of the drug. It is what is known as a Type B reaction. Type B reactions have the following characteristics: they are usually unpredictable, might not be picked up by toxicological screening, not necessarily dose-related, incidence and morbidity low but mortality is high. Type B reactions are most commonly immunological (e.g. penicillin allergy).[6]
The word is used for the personal way a given individual reacts, perceives and experiences: a certain dish made of meat may causenostalgic memories in one person and disgust in another. These reactions are calledidiosyncratic.[7]
Inportfolio theory, risks of price changes due to the unique circumstances of a specific security, as opposed to the overall market, are called "idiosyncratic risks". This specific risk, also called unsystematic, can be nulled out of a portfolio through diversification. Pooling multiple securities means the specific risks cancel out. Incomplete markets, there is no compensation for idiosyncratic risk—that is, a security's idiosyncratic risk does not matter for its price. For instance, in a complete market in which thecapital asset pricing model holds, the price of a security is determined by the amount ofsystematic risk in its returns. Net income received, or losses suffered, by alandlord fromrenting of one or two properties is subject to idiosyncratic risk due to the numerous things that can happen to real property and variable behavior of tenants.[8]
According to one macroeconomic model including a financial sector,[9] hedging idiosyncratic risk can be self-defeating as amid the "risk reduction" experts are encouraged to increase their leverage. This works for small shocks but leads to higher vulnerability for larger shocks and makes the system less stable. Thus, while securitisation in principle reduces the costs of idiosyncratic shocks, it ends up amplifying systemic risks in equilibrium.[citation needed]
Ineconometrics, "idiosyncratic error" is used to describe error—that is, unobserved factors that impact the dependent variable—frompanel data that both changes over time and across units (individuals, firms, cities, towns, etc.)[citation needed]
The dictionary definition ofidiosyncrasy at Wiktionary