Any of a large group of antibiotics with a molecular structure containing four rings.
- ‘It is well established that far less expensive antibiotics, including the penicillins and tetracyclines, are highly effective against Anthrax.’
- ‘This strain was resistant to methicillin, cephalothin, gentamicin, erythromycin, chloramphenicol and tetracycline.’
- ‘Moderate acne is often successfully treated with a low-dose oral antibiotic, such as tetracycline or erythromycin.’
- ‘Some antibiotics, such as tetracycline, are not fully effective when taken with milk or dairy products.’
- ‘He was treated with a six-month course of a tetracycline and made a slow and steady recovery.’
1950s: from tetra- + cyclic + -ine.