Definition
Latin. Literally "in one breath." A maxim expressing that two or more acts, events, or legal consequences occur simultaneously, instantaneously, or in a single unified moment — so inseparably connected that they cannot be treated as sequential or independent. The phrase appears in legal argument to assert that two things happened at the same time and with the same intent, such that no legal significance can attach to any supposed interval between them.
The fuller phrase uno flatu et uno intuitu — "in one breath, and in one view" — extends the idea to cover not only temporal simultaneity but perceptual or intentional unity: the acts are perceived, intended, or legally treated as a single whole rather than as a series.
A related maxim, uno absurdo dato, infinita sequuntur ("one absurdity being allowed, numbers without end follow"), appears in the same doctrinal neighborhood and is sometimes cited alongside uno flatu to reinforce the logical stakes of treating a legal moment as divisible when it is not.
Common Language
Modern (Wiktionary): "At once, at one blast, at the same moment, contemporaneously, simultaneously."
The common meaning tracks the legal meaning closely in a literal sense, but the legal application carries a specific argumentative weight that ordinary usage does not. In legal contexts, uno flatu is not merely a description of timing — it is a claim about legal indivisibility. To say two acts occurred uno flatu is to argue that no legal consequence, intervening right, or independent liability can be attached to either act in isolation. The phrase does work that "simultaneously" alone does not.
Common Confusion
Uno flatu is sometimes conflated with the broader concept of contemporaneous acts or the doctrine of simultaneous death. The distinction matters: uno flatu is a maxim of logical and legal unity, not merely a factual claim about timing. It asserts that the acts are so fused in legal contemplation that they must be analyzed as one. It should also be distinguished from in instanti ("in an instant"), which describes instantaneous occurrence without necessarily implying the indivisibility or unified intent that uno flatu carries.
Why It Matters in Research
Researchers will encounter uno flatu most often in older common law opinions and treatises, where Latin maxims carried structural argumentative weight. The phrase appears in contract, tort, and procedural contexts to defeat arguments that rely on parsing a sequence of events. If a party claims, for example, that a right vested between two acts, an opposing argument framed uno flatu collapses that interval as legally meaningless.
The key research trap is treating uno flatu as a mere stylistic flourish. In historical sources, this maxim signals a substantive legal argument about indivisibility — one that courts actually engaged with. Researchers working in equity, early federal case law, or admiralty will encounter it most frequently. Pope v. Nickerson (3 Story 504, Fed. Cas. No. 11,274) is the most commonly cited American case using the phrase and is the anchor citation in both Black's editions.
The phrase virtually disappears from modern judicial writing, replaced by plain-English equivalents. Researchers searching modern databases for the underlying concept should use terms like "simultaneous," "inseparable acts," or "single transaction rule" rather than the Latin.
Historical Dictionary Support
The historical dictionaries are in agreement on the core definition: "in one breath," indicating simultaneity and unity of act or intent. Burrill's is the most substantive, providing two illustrative contexts: the procedural/logical sense (from Leonard's Reports) and the fuller phrase uno flatu et uno intuitu (from Story's Reports). Burrill also preserves the companion maxim uno absurdo dato, infinita sequuntur, correctly situating uno flatu within a cluster of Latinate reasoning tools used in common law argument.
Black's first and second editions are consistent with each other and with Burrill, with the second edition usefully upgrading the citation to the full Federal Cases reference. Rapalje & Lawrence compress the meaning to "at the same moment, and with the same intent" — accurate but without the illustrative context that Burrill provides.
None of the historical dictionaries explain the argumentative function of the phrase — why a party would invoke it and what it was meant to defeat. That gap is the primary limitation of the historical record on this term.
Encyclopedia Cross-Reference
No Law Mind Encyclopedia entry directly addresses Latin maxims or the doctrine of legal indivisibility. The matched entry (Organ Transplantation Law, health_57) is not relevant to this term.