Clinical Research Glossary
Every study wordhas a plainmeaning.
Trial Terms Dictionary makes clinical research terminology easier to understand through plain-language definitions and examples. Learn the vocabulary before you read a study listing or talk with a study team.
$ define placebo
A look-alike with no active ingredient,
used to compare results fairly.
Five starter guides
Clinical Research Terms by study type
- 01
General Clinical Research
The core vocabulary that appears in almost every study description.
ProtocolInformed consentEligibility criteriaEndpointAdverse event
- 02
Randomized Studies
Words that describe how volunteers are fairly assigned to groups.
RandomizationArmControl groupCrossover design
- 03
Placebo-Controlled Studies
Terms for studies that compare an approach with an inactive look-alike.
PlaceboPlacebo effectBlindingWashout period
- 04
Observational Research
Language for studies that watch and record rather than assign.
Observational studyCohortLongitudinal studyRetrospective study
- 05
Early-Phase Research
Vocabulary for the first, smallest stages of testing.
PhaseFirst-in-human studyHealthy volunteerDose escalation
Weekly vocabulary
Term of the week
Randomization
Term of the week: Randomization
Why studies use chance, not choice, to decide who goes into which group.
Read the articleHow it works
From confusing to clear in four steps
No sign-up needed to read. Texts are optional and always educational.
- 01
Look up a word
Search the glossary for any term you spot on a study listing or consent page.
- 02
Read it plainly
Each entry pairs a short definition with an everyday example you can picture.
- 03
Check yourself
Short quizzes help the new vocabulary stick before your next conversation.
- 04
Keep learning by text
Optionally choose vocabulary lessons or new glossary entries sent by SMS.
Questions
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Yes. Every glossary entry, guide, quiz, and article is free to read without creating an account or signing up.
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Search hundreds of research words with plain definitions and examples.
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Any trial programs or research organizations mentioned on Trial Terms Dictionary are independent organizations operating under their own protocols and eligibility criteria. Trial Terms Dictionary does not control, supervise, guarantee, or take responsibility for the protocols, eligibility criteria, safety monitoring, outcomes, or conduct of any independent clinical trial program. Review the materials provided by the independent organization and consult your own licensed healthcare provider before deciding to participate.