Definition
A Latin adverbial phrase meaning "after this," "after the present time," or "hereafter." Used in legal instruments, pleadings, and judicial writing to signal that what follows applies to future circumstances, as distinct from what has already occurred or what is presently at issue. Functionally equivalent to "henceforth" or "from this point forward."
Common Language
Modern common usage (Wiktionary): Not in general modern English use; survives primarily in scholarly and legal Latin contexts.
Historical common usage (Webster's 1913): Not separately defined; subsumed under general Latin borrowings common to legal and ecclesiastical writing of the period.
Editorial note: Because posthac has no meaningful life outside formal Latin usage, the gap between "common" and "legal" meaning is negligible — the term carries no competing vernacular sense that could mislead a researcher. Its risk is unfamiliarity, not ambiguity.
Common Confusion
Posthac is occasionally confused with post hoc, a distinct Latin phrase meaning "after this" in the logical sense — as in the informal fallacy post hoc ergo propter hoc ("after this, therefore because of this"). The two phrases are related etymologically but serve entirely different functions. Post hoc appears in logical, rhetorical, and evidentiary contexts; posthac appears in instruments and judicial language to mark temporal scope or prospective effect. A researcher encountering "post hoc" in a brief arguing causation is reading something categorically different from "posthac" in a deed or court order establishing what rules apply going forward.
Why It Matters in Research
Posthac surfaces most often in older instruments — deeds, court orders, settlements, and procedural writs — where Latin shorthand for temporal reference was routine. Researchers working in pre-twentieth-century American or English legal documents should treat it as a drafting term of art signaling prospective rather than retroactive application. If a clause begins with posthac, the operative provision that follows was intended to govern future conduct or future legal relations only, which can be decisive when the question before a court is whether an instrument applied to events before or after its execution.
The term largely disappeared from American legal drafting after the plain-language reform movement of the mid-to-late twentieth century. Modern instruments substitute "hereafter," "from and after the date hereof," or equivalent English phrases. Researchers reading across that historical divide should recognize posthac as the functional ancestor of those modern formulations and treat them as interchangeable for interpretive purposes.
Because the term appears only in the supplemental material to Black's Second Edition, rather than the main entries, its presence in the Law Mind corpus may be sparse. Researchers should not conclude from the brevity of the dictionary treatment that the term was obscure in practice — Latin temporal markers of this kind were common drafting conventions, and their absence from fuller treatment in historical dictionaries reflects editorial assumptions about reader familiarity, not rarity of use.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) Supplemental defines posthac tersely as "After this; after the time; hereafter" — a three-part gloss that correctly captures the term's temporal and prospective orientation without elaboration. The definition is accurate as far as it goes. No other shelf sources in the Law Mind corpus provide independent entries, which is consistent with the term's status as standard legal Latin that reference compilers of the period assumed practitioners would recognize without extended explanation. The brevity of the historical record is not a gap in scholarship so much as a reflection of how thoroughly Latin legal vocabulary was embedded in the working knowledge of the bar through at least the early twentieth century.