From Longman Dictionary of Contemporary Englishdecreasede‧crease1 /dɪˈkriːs/ ●●○ verb [intransitive, transitive] LESSto become less or go down to a lower level, or to make something do this → reduce OPP increase The number of people who have the disease has decreased significantly in recent years. They want to decrease their reliance on oil.decrease by Average house prices decreased by 13% last year.decrease to By 1881, the population of Ireland had decreased to 5.2 million.decrease from The North’s share of the world’s energy consumption is expected to decrease from 70% to 60%.decrease in Attacks of asthma decrease in frequency through early adult life.GrammarDecrease belongs to a group of verbs where the same noun can be the subject of the verb or its object. • You can say: They decreased the number of buses. In this sentence, ‘the number of buses’ is the object of decrease.• You can say: The number of buses decreased. In this sentence, ‘the number of buses’ is the subject of decrease.COLLOCATIONSadverbssignificantly (=enough to be an important change)Violent crime has significantly decreased over the last ten years.considerably/substantially (=a lot)During this period unemployment decreased considerably.markedly (=very noticeably)Aircraft collisions decreased markedly during the 1990s.rapidly (=very quickly)Since then, elephant numbers have been decreasing rapidly.dramatically (=suddenly and a lot)The survival rate decreases dramatically as the disease progresses.slightly (=a little)Population levels actually began to slightly decrease five years ago.steadily (=gradually and continuously)The proportion of adult cigarette smokers has been steadily decreasing. THESAURUSdecrease to become less in number or amountThe average rainfall has decreased by around 30 percent.go down to decrease. Go down is less formal than decrease and is the usual word to use in conversationUnemployment has gone down in the past few months.decline formal to decrease – used with numbers or amounts, or about the level or standard of somethingThe standard of living has declined.Support for the government is steadily declining.Salaries have declined by around 4.5%.diminish to become smaller or less importantUnion membership diminished from 30,000 at its height to just 2,000 today.fall/drop to decrease, especially by a large amount. Fall and drop are less formal than decreaseThe number of tigers in the wild has fallen to just over 10,000.At night, the temperature drops to minus 20 degrees.plunge /plʌndʒ//plummet /ˈplʌmət/ to suddenly decrease very quickly and by a very large amountShare prices have plummeted 29% in the last four months.Climate change could cause global temperatures to plummet.slide if a price or value slides, it gradually decreases in a way that causes problems – used especially in news reportsThe dollar fell in late trading in New York yesterday and slid further this morning.dwindle /ˈdwɪndl/ to gradually decrease until there is very little left of something, especially numbers or amounts, popularity, or importanceSupport for the theory is dwindling.taper off /ˈteɪpə $ -ər/ if a number or the amount of an activity that is happening tapers off, it gradually decreases, especially so that it stops completelyPolitical violence tapered off after the elections. → See Verb table
Examples from the Corpus
decrease• Experts say that the time parents spend with their children is decreasing.• Histamine secretion was decreased about sixfold in all groups at day 7 compared with day 3.• Other complications of pregnancy were found to decrease almost linearly with age of women.• The second possibility is for supply to decrease and demand to increase.• Texaco had lifted capital spending 11 % last year, after decreasing it in 1993 and 1994.• Sales in Japan decreased last quarter.• This will increase rather than decrease pollution.• Their use decreased slightly in September, to 149 reported instances.• Birth control pills decrease the chances of getting pregnant.• Supplementary dietary phosphate decreased the fatty acid concentration only on the low calcium diet.• Better health education should help to decrease the incidence of heart disease.• Use of the new nets has significantly decreased the number of dolphins killed accidentally each year.• Various methods are being explored in order to decrease the volume of traffic on our roads.• The speed of rotation gradually decreases to zero.• They also delay sleep onset, increase the chances of waking after sleep onset occurs, and decrease total sleep time.decrease in• Some illnesses cause a decrease in appetite.• a 19% decrease in pricesdecreasede‧crease2 /ˈdiːkriːs/ ●●○ noun [countable, uncountable] REDUCEthe process of becoming less, or the amount by which something becomes less OPP increase SYN reductiona decrease in something Teachers reported decreases in drug use and verbal abuse of teachers.a decrease of 50/5% etc There has been a decrease of 1 degree in average temperature.THESAURUSdecrease used when the number, amount, or level of something becomes less than it used to beThere has been a significant decrease in the number of deaths from lung cancer.a 5% decrease in housing pricesreduction used when the price, amount, or level of something is made lowerThere will be further price reductions in the sales.A small reduction in costs can mean a large increase in profits.cut used when a government or company reduces the price, amount, or level of somethinga 1% cut in interest ratestax cutsIt is possible that there will be further job cuts.drop/fall used when the number, amount, or level of something goes down, especially by a large amountThe figures showed a sharp fall in industrial output.There was a dramatic drop in temperature.decline used when the number, amount, level, or standard of something goes down, especially graduallyDuring the 1970s, there was a gradual decline in the birthrate.a decline in educational standardsExamples from the Corpus
decrease• Fewer consumers will be reflected by a decrease in demand.• The Schirmer and break up time test confirmed a decrease of tear secretion.• It forecast a decrease of 5,000 for 1987-88; in fact, the decrease was 7,800.• When resorption overtakes formation, the result is a decrease in bone density and strength.• It focused on the fact that none of the trials showed a decrease in mortality within seven years of follow-up.• Mechanization has not therefore necessarily involved any decrease in job satisfaction among farm workers.• a 5 percent decrease in the value of the dollar• In the last five years there has been a significant decrease in the number of deaths from heart disease.• a significant decrease in the number of deaths from heart diseaseFrom Longman Business Dictionarydecreasede‧crease1 /dɪˈkriːs/ verb [intransitive, transitive] to go down to a lower level, or to make something do thisNetwork television viewing continues to decrease.The bank decreased its dividend to 15 cents from 31.25 cents a share. —decreasing adjective [only before a noun]The airline has been hurt by high fuel costs and decreasing passenger traffic.→ See Verb tabledecreasede‧crease2 /ˈdiːkriːs/ noun [countable, uncountable] the process of reducing something, or the amount by which it reducesdecrease inThe government announced a 25% decrease in the price of fuel.decrease ofIndustrial production last month rose 0.5%, after a decrease of 0.2% in December.Origin decrease1 (1300-1400) Anglo-French decreistre, from Latin decrescere, from crescere “to grow” 