opioid

American  

[oh-pee-oid] / ˈoʊ piˌɔɪd /

noun

Biochemistry, Pharmacology.

1. an opiate, or any similar synthetic compound: formerly referring only to the latter, but now the predominant term for both the opium-derived and synthetically produced substances.

   Illicit use of the synthetic opioid fentanyl is on the rise.

   The opium poppy is the source for all natural opioids.

2. any opiumlike substance.

   Have any opioids been detected in poppies that do not contain opium?

3. any of a group of natural substances, as the endorphins, produced by the body in increased amounts in response to stress and pain.

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adjective

1. pertaining to such a substance.

   opioid drugs such as heroin and oxycodone;

   opioid neuropeptides.

opioid British  

/ ˈəʊpɪˌɔɪd /

noun

1. 1. any of a group of substances that resemble morphine in their physiological or pharmacological effects, esp in their pain-relieving properties

   2. (modifier) of or relating to such substances

      opioid receptor

      opioid analgesic

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Etymology

Origin of opioid

First recorded in 1955–60; opi(um) + -oid

Example Sentences

The Pitt covers everything from a measles outbreak, a shooting at a festival, the opioid crisis, medical abortion, black maternal care, homelessness and more besides.

From BBC • Mar. 27, 2026

Kaufmann stepped down after steering the company through an onslaught of litigation related to the opioid crisis.

From Barron's • Feb. 5, 2026

Since the ’70s, many other studies have confirmed that placebos can activate opioid receptors, as well as dopamine receptors, which are part of the body’s internal reward system.

From Slate • Jan. 30, 2026

The cases are using a similar script to past ones accusing pharmaceutical companies of perpetuating the opioid epidemic or tobacco companies of failing to warn about harm from cigarettes, cases that led to multibillion-dollar settlements.

From The Wall Street Journal • Jan. 26, 2026

These findings deepen scientific understanding of opioid biology and move researchers closer to developing safer, non-addictive pain treatments.

From Science Daily • Jan. 6, 2026