What word prevalence means
Word prevalence estimates how many people know a word. For example, serendipity is widely known, while tergiversation is obscure.
It is useful when you want to know whether a word will be familiar to your readers.
How obscure is this word?
Search for a word to see what percentage of English speakers know it.
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Word prevalence vs word frequency
Frequency counts how often a word appears in texts. Prevalence estimates how many people recognize it. For general readability, prevalence is the better tool. A specialist term can be frequent in one field but unfamiliar to general readers.
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Guides
How Common Is This Word?See what percentage of English speakers know a word.Word Prevalence vs Word FrequencyHow word familiarity differs from how often a word appears in text.About Word PrevalenceA plain-English explanation of word prevalence, percent known, and rarity labels.SourcesResearch and dictionary sources used by the site.
Word lists
Most common wordsFamiliar words with very high recognition rates.Rare wordsWords many readers may not recognize.Rarest wordsObscure words with low recognition rates.Academic wordsSchool, research, and analytical vocabulary checked for reader familiarity.SAT vocabulary wordsVocabulary-study words with recognition estimates.GRE vocabulary wordsAdvanced vocabulary with recognition estimates.Words known by about 90 percentWords near the line between broadly familiar and less universal.Words known by about 75 percentWords many readers know, but many others may not.Words known by about 50 percentWords where reader familiarity is genuinely uncertain.Words known by under 25 percentVery obscure words, usually limited to specialist contexts.Commonly known hard wordsLong or academic-looking words that many readers still know.Surprisingly rare wordsWords that look useful but are less widely known than they may seem.