Definition of bug noun from the Oxford Advanced Learner's Dictionary

bug

noun

bʌɡ

bʌɡ

1 [countable] (especially North American English) any small insect2 [countable] (informal) an infectious illness that is usually fairly milda flu bugThere's a stomach bug going round (= people are catching it from each other).I picked up a bug in the office.3 (usually the… bug) [singular] (informal) an enthusiastic interest in something such as a sport or a hobbythe travel bugShe was never interested in fitness before but now she's been bitten by the bug.4 [countable] (informal) a small hidden device for listening to other people's conversationsThey planted a bug in his hotel room.5 [countable] a fault in a machine, especially in a computer system or program6 [countable] (North American English) = Beetle

Usage note: IllnessesBecoming illcatch a cold/an infectious disease/the flu/(British English) flu/pneumonia/a virus/(informal) a bugget (British English) ill/(North American English) sick/a disease/AIDS/breast cancer/a cold/the flu/(British English) flu/a migrainecome down with a cold/the flu/(British English) flucontract a deadly disease/a serious illness/HIV/AIDSbe infected with a virus/a parasite/HIVdevelop cancer/diabetes/a rash/an ulcer/symptoms of hepatitishave a heart attack/a strokeprovoke/trigger/produce an allergic reactionblock/burst/rupture a blood vesseldamage/sever a nerve/an artery/a tendonBeing illfeel (British English) ill/sick/nauseous/queasybe running (British English) a temperature/(North American English) a feverhave a head cold/diabetes/heart disease/lung cancer/a headache/(British English) a high temperature/(North American English) a feversuffer from asthma/malnutrition/frequent headaches/bouts of depression/a mental disorderbe laid up with/(British English) be in bed with a cold/the flu/(British English) flu/a migrainenurse a cold/a headache/a hangoverbattle/fight cancer/depression/addiction/alcoholismTreatmentsexamine a patientdiagnose a condition/disease/disorderbe diagnosed with cancer/diabetes/schizophreniaprescribe/be given/be on/take drugs/medicine/medication/pills/painkillers/antibioticstreat somebody for cancer/depression/shockhave/undergo an examination/an operation/surgery/a kidney transplant/therapy/chemotherapy/treatment for cancerhave/be given an injection/(British English) a flu jab/(North American English) a flu shot/a blood transfusion/a scan/an X-raycure a disease/an ailment/cancer/a headache/a patientprevent the spread of disease/further outbreaks/damage to the lungsbe vaccinated against the flu/(British English) flu/the measles/(British English) measles/polio/smallpoxenhance/boost/confer/build immunity to a disease

Usage note: diseaseillness disorder infection condition ailment bugThese are all words for a medical problem.disease a medical problem affecting humans, animals or plants, often caused by infection: He suffers from a rare blood disease.illness a medical problem, or a period of suffering from one: She died after a long illness.disease or illness?Disease is used to talk about more severe physical medical problems, especially those that affect the organs. Illness is used to talk about both more severe and more minor medical problems, and those that affect mental health: heart/kidney/liver illness ◇ mental disease. Disease is not used about a period of illness: she died after a long diseasedisorder (rather formal) an illness that causes a part of the body to stop functioning correctly: a rare disorder of the liver. A disorder is generally not infectious. Disorder is used most frequently with words relating to mental problems, for example psychiatric, personality, mental and eating. When it is used to talk about physical problems, it is most often used with blood, bowel and kidney, and these are commonly serious, severe or rare.infection an illness that is caused by bacteria or a virus and that affects one part of the body: a throat infectioncondition a medical problem that you have for a long time because it is not possible to cure it: a heart conditionailment (rather formal) an illness that is not very serious: childhood ailmentsbug (informal) an infectious illness that is usually fairly mild: a nasty flu bugto have/suffer from a(n) disease/illness/disorder/infection/condition/ailment/bugto catch/contract/get/pick up a(n) disease/illness/infection/bug