Definition
In patent law, a trial or test conducted by an inventor to develop, refine, or verify an invention. Two distinct situations arise:
1. Experiment on an incomplete structure. A trial conducted on an unfinished device to determine what modifications are needed to make it work as intended. If the inventor abandons the effort at this stage, the experiment does not constitute prior public use and will not bar a later patent claim.
2. Experiment on a completed machine. A trial of a finished device to test its practical efficiency or demonstrate its operation. Whether this type of experiment affects patent rights depends heavily on whether the use was genuinely experimental in character or instead constituted a public use that triggers the statutory bar.
The distinction matters because the law allows inventors time to test and perfect their inventions without losing patent rights, but it does not permit an inventor to commercially exploit a completed invention while indefinitely delaying a patent application under the guise of ongoing experimentation.
Common Language
Modern common usage (Wiktionary): A test under controlled conditions made to demonstrate a known truth, examine a hypothesis, or determine the efficacy of something previously untried. Also, experience or practical familiarity with something.
Historical common usage (Webster's 1913): A trial or special observation made to confirm or disprove something doubtful; an act undertaken to discover an unknown principle or effect, or to test an established truth; practical proof.
The ordinary meaning of experiment is broader and value-neutral — any systematic test qualifies. The legal meaning in patent law is narrower and purposive: an experiment must be genuinely directed at completion or verification of an invention, not at commercial use or public deployment. A researcher encountering "experiment" in patent cases should not assume the common meaning applies; courts scrutinize the intent and circumstances behind claimed experimental use carefully.
Common Confusion
Experiment vs. public use. The experimental use doctrine is a recognized exception to the public use bar in patent law, but the two concepts are frequently conflated. A use that appears experimental in the ordinary sense — observing how a product performs in real-world conditions — may still constitute a disqualifying public use if the primary purpose was commercial exploitation rather than genuine testing. The label "experiment" does not control; courts look to the totality of circumstances.
Why It Matters in Research
The legal significance of experiment in the Law Mind corpus is almost entirely confined to patent law, specifically the experimental use doctrine and its relationship to the public use bar. Researchers should be alert to several navigational issues:
First, the doctrine's boundaries shifted considerably through the nineteenth and twentieth centuries. Early American patent cases gave inventors relatively generous latitude to test inventions in public settings without triggering the use bar. Later decisions narrowed this, requiring clearer evidence that testing — not commercial benefit — was the controlling purpose.
Second, Anderson's entry redirects to INVENTION, signaling that the term does not stand alone in older treatise literature. Researchers working with Anderson's should follow that cross-reference and read experiment as a subordinate concept within the broader framework of invention and priority.
Third, Black's 2nd edition entry is truncated in available sources, cutting off mid-sentence at the point of discussing the effect of abandonment on subsequent inventors' rights. Researchers relying on this edition should be aware the entry is incomplete as reproduced and may be missing material doctrine.
Fourth, the term appears in non-patent contexts — contracts involving research and development obligations, tort cases involving medical or scientific testing, and administrative law governing agency-authorized pilot programs — but in those contexts it carries its ordinary meaning rather than a technical legal one. Do not import patent law's experimental use framework into those other settings without jurisdiction-specific support.
Historical Dictionary Support
Black's 2nd edition provides the most substantive historical definition, drawing the useful distinction between experiments on incomplete versus completed structures. This two-part framework aligns with how courts of the era analyzed experimental use: the incomplete-structure scenario more clearly protects the inventor, while the completed-machine scenario requires closer examination of whether the bar has been triggered. Anderson's offers no independent definition, deferring entirely to INVENTION — a choice that reflects how integrated the concept of experiment was within the broader law of patents in that period rather than treated as a freestanding doctrine.
Neither source addresses experimental use in non-patent contexts, which reflects their orientation toward common law and patent doctrines of the late nineteenth century. Modern researchers should not assume these entries capture the full contemporary scope of the term across practice areas.
Encyclopedia Cross-Reference
For context on experience-based legal frameworks in adjacent areas, see: Employer Challenges and Experience Rating (The Law Mind Employment & Labor Law Encyclopedia, employment_137). Note that this entry concerns experience rating in employment law — a distinct usage — not the patent law doctrine of experimental use. The connection is terminological only.