Trends & Quantity — TOEFL Academic Vocabulary
Trends Five high-utility words with the full apparatus: pronunciation, both definitions, natural + academic examples, collocations, family, mistakes — then a 10-question set quiz.
increase /ɪnˈkriːs/ verb B1
Meaning: to become bigger in number or amount
Academic meaning: to rise in quantity, degree, or frequency, often measured over a defined period
Natural example: The price of gas increased again last month.
Academic example: Between 2000 and 2020, the proportion of older adults in the population increased steadily.
Collocations: increase significantly · increase by 10 percent · an increase in number
Synonyms: rise, grow, climb
Antonyms: decrease, decline
Word family: increase (verb) · increase (noun) · increasing (adjective) · increasingly (adverb)
⚠ Common mistake: Confusing 'increase by' (the size of the change) with 'increase to' (the final level): 'rose by 10' is not 'rose to 100'.
Register: neutral; a core academic verb · Usage: Watch the stress: the verb is inCREASE, while the noun is INcrease.
decline /dɪˈklaɪn/ verb B2
Meaning: to become smaller, fewer, or weaker
Academic meaning: to decrease gradually in quantity, quality, or importance over a period of time
Natural example: Sales of printed newspapers decline a little more every year.
Academic example: The species has declined sharply since the 1980s, largely because of habitat loss.
Collocations: decline sharply · a steady decline · decline in numbers
Synonyms: decrease, fall, drop
Antonyms: increase, rise
Word family: decline (verb) · decline (noun) · declining (adjective)
⚠ Common mistake: Knowing 'decline' only as polite refusal ('decline an invitation') and missing its main data sense: gradual downward movement.
Register: neutral to formal · Usage: Preferred over 'go down' in academic writing; typically modified by degree: decline sharply, steadily, or gradually.
trend /trend/ noun B2
Meaning: the general direction in which something is changing
Academic meaning: a general pattern of movement or development shown by data over time
Natural example: The latest trend on campus is carrying a reusable water bottle.
Academic example: The data reveal a clear upward trend in average global temperatures.
Collocations: an upward trend · a downward trend · a trend towards
Synonyms: pattern, tendency, direction
Word family: trend (noun) · trend (verb) · trendy (adjective)
⚠ Common mistake: Using 'trend' for a single change or one data point — a trend requires movement across several points over time.
Register: neutral; academic and media · Usage: Almost always described with a direction or quality: upward, downward, clear, recent, or general trend.
rate /reɪt/ noun B1
Meaning: the speed or frequency at which something happens; a measured amount
Academic meaning: a quantity measured in relation to another unit, typically expressing frequency or speed over time
Natural example: Interest rates went up again this year, so loans cost more.
Academic example: The unemployment rate fell to its lowest level in a decade.
Collocations: the rate of change · the unemployment rate · at a rate of
Synonyms: speed, pace, frequency
Word family: rate (noun) · rate (verb) · rating (noun)
⚠ Common mistake: Confusing 'rate' with 'ratio' or 'price' — in data contexts, a rate is an amount per unit of time or per unit of population.
Register: neutral; a core data noun · Usage: Standard in data description: birth rate, growth rate, survival rate, and the pattern 'at a rate of 5 percent per year'.
proportion /prəˈpɔːrʃən/ noun B2
Meaning: a part of a whole, shown as a fraction or a percent
Academic meaning: the share of a total represented by a subgroup, often expressed as a fraction, ratio, or percentage
Natural example: A large proportion of students at this college live near the campus.
Academic example: The proportion of women in engineering rose from 12 to 21 percent over the period.
Collocations: a large proportion of · the proportion of X to Y · in proportion to
Synonyms: percentage, share, fraction
Word family: proportion (noun) · proportional (adjective) · proportionately (adverb) · disproportionate (adjective)
⚠ Common mistake: Using 'proportion' for any amount — it always relates a part to a whole; for a raw amount with no whole, use 'number' or 'amount'.
Register: formal; academic data writing · Usage: It takes 'of': 'the proportion of students who…' — and in careful writing the verb agrees with the noun after 'of'.