Definition
"Best" as a standalone legal term functions primarily as a qualifying adjective within compound legal standards and doctrines rather than as an independent term of art. Its legal significance arises from context: the same word carries distinct operative meanings depending on the legal framework in which it appears. Three principal legal usages predominate:
1. Best interests (of the child): The governing standard in child custody, guardianship, and related family law proceedings. Courts assess what outcome best promotes the welfare, safety, and development of the minor child, considering a constellation of statutory and common-law factors. The standard is deliberately flexible and fact-specific, granting courts broad discretion.
2. Best efforts: A contractual standard of performance requiring a party to exert the highest degree of diligence and good faith in pursuing a contractual obligation, generally understood to impose a more demanding duty than "reasonable efforts" or "commercially reasonable efforts," though courts vary on whether the terms are truly distinct.
3. Best evidence (rule): A rule of evidence requiring that, when the contents of a document are at issue, the original document must be produced unless its absence is adequately explained. Modern codifications have substantially relaxed this rule.
In trust and estate contexts, "best" may also appear in discretionary trust language — as in bequest provisions directing a trustee to pay income or such portion "as he may consider best" — where courts construe the word as a grant of fiduciary discretion oriented toward the beneficiary's welfare.
Common Language
Modern common usage (Wiktionary): Superlative of good; most good, most superior, most favorable.
Historical common usage (Webster's 1913): Having good qualities in the highest degree; most excellent, most desirable, most correct, or most complete.
The common meaning of "best" is superlative and comparative — it describes the most favorable option among alternatives. In law, the word rarely operates as a pure superlative. Instead, it anchors defined legal standards (best interests, best efforts, best evidence) with specific doctrinal content that a researcher cannot derive from the ordinary English meaning alone. Identifying which legal standard the word is part of is the essential first analytical step.
Common Confusion
Best efforts vs. reasonable efforts vs. commercially reasonable efforts: These three contractual performance standards are frequently treated as interchangeable in drafting and litigation, but courts in many jurisdictions treat them as an ascending hierarchy of obligation — with "best efforts" at the top — while others collapse the distinction entirely. The confusion is compounded because historical sources treat "best efforts" as a settled concept, while modern commercial practice often disfavors the term precisely because of the doctrinal uncertainty it generates.
Best interests standard vs. parens patriae doctrine: The best interests of the child standard is the adjudicative test applied by courts in specific proceedings; parens patriae is the broader state authority that justifies the court's intervention in the first place. Historical sources sometimes conflate these or treat best interests as a self-evident extension of parens patriae without distinguishing the standards they impose.
Why It Matters in Research
Because "best" functions differently in different legal contexts, corpus searches on the unmodified term will retrieve highly heterogeneous material. Researchers should search for the compound phrase — "best interests," "best efforts," "best evidence rule" — rather than the standalone word.
In family law materials, the best interests standard has undergone significant evolution. Nineteenth- and early twentieth-century cases often embedded gendered presumptions (the tender years doctrine) within what was nominally a best-interests analysis. Historical sources may describe the standard in ways that overstate judicial certainty or mask the presumptions doing the actual work. Researchers using historical family law materials should interrogate whether the stated standard and the applied standard are the same.
In contracts materials, the best efforts doctrine presents a notable research trap: historical sources, including treatises and early case law, tend to treat "best efforts" as demanding near-absolute performance. Modern commercial law — particularly in transactions-oriented jurisdictions — has moved toward reading best efforts as equivalent to, or only marginally more demanding than, commercially reasonable efforts. A researcher relying solely on historical dictionary or treatise sources will find an obligation that modern courts may not recognize.
The best evidence rule warrants similar caution. The traditional formulation found in historical dictionaries reflects a more rigid rule than modern evidence codes impose. Federal Rule of Evidence 1002 and its state analogs substantially modernized the doctrine; historical sources predating these codifications describe a stricter regime.
In trust and estate research, discretionary trust language using "best" — as in the Anderson's example of a trustee paying income "as he may consider best" — should be read against the equitable standards governing trustee discretion in the relevant jurisdiction and era. Courts have interpreted such language as fiduciary in character, not purely subjective, which limits the trustee's freedom more than the plain words might suggest.
Historical Dictionary Support
Anderson's Dictionary of Law does not define "best" as an independent entry but directs the reader to BID, EVIDENCE, and KNOWLEDGE — a telling editorial choice that confirms the term's derivative character. The illustrative example Anderson provides concerns a discretionary trust bequest, and the gloss offered — that "best" had more reference to withholding income than paying it — reflects a court's effort to anchor a fiduciary standard of care within open-ended testamentary language. This usage is consistent with the broader historical pattern of courts treating apparent grants of subjective discretion as implicitly constrained by objective beneficiary-welfare standards.
Historical legal dictionaries generally treat "best evidence" most extensively, reflecting the rule's prominence in nineteenth-century evidence law. "Best efforts" as a distinct contractual standard receives comparatively thin treatment in historical sources, suggesting its emergence as a fully theorized doctrine is largely a twentieth-century development. "Best interests of the child" as a formal standard is essentially absent from pre-twentieth-century dictionaries as a named doctrine, even where the underlying concern for child welfare is present.
Jurisdictional Note
The best interests of the child standard is statutory in most U.S. jurisdictions, with legislatures enumerating the factors courts must consider; the weight given to each factor varies significantly by state. The best efforts standard in contract law is treated most distinctly from reasonable efforts in Delaware and New York; other commercial jurisdictions often collapse the distinction. The best evidence rule is codified at the federal level and in most state evidence codes, but the codified version differs meaningfully from the common-law formulation found in historical sources.
Encyclopedia Cross-Reference
family_67: Child Custody — Overview and Best Interests of the Child Standard (The Law Mind Family Law Encyclopedia)
family_70: Child Custody — Factors in Determining Best Interests (The Law Mind Family Law Encyclopedia)
contracts_44: Interpretation — Best Efforts Clauses and Reasonable Efforts Standards (The Law Mind Contracts & Commercial Law Encyclopedia)