Definition
In law, confidence carries two related but distinct senses.
1. Trust as a legal relationship. Confidence denotes the reliance one person places in another who accepts an obligation to act in the first person's interest. In this sense, confidence is functionally synonymous with trust: a trust is a confidence reposed in a trustee, and confidence is the mental and relational foundation on which a trust rests. Courts and courts of equity have long used the word in this sense when construing instruments — particularly wills — to identify fiduciary or trust obligations even where the word "trust" does not appear.
2. Confidential information. Confidence also describes information communicated privately with the expectation that it will not be disclosed. The phrase "breach of confidence" names the cause of action or equitable obligation that arises when a person who receives information in circumstances importing confidentiality uses or discloses it without authorization. This sense underlies obligations between attorneys and clients, physicians and patients, and parties in commercial relationships involving trade secrets or proprietary data.
---
Common Language
Modern common usage (Wiktionary): Self-assurance; a feeling of certainty or firm belief; information shared but kept secret; boldness.
Historical common usage (Webster's 1913): The act of trusting or putting faith in another; reliance; the thing in which faith is placed; also, the state of mind characterized by assurance.
The gap worth noting: ordinary English uses "confidence" most often to mean self-assurance or psychological certainty — the internal state of a person. Legal usage centers instead on a relational obligation: the duty owed by the person in whom confidence is reposed, not the feeling of the person who reposes it. A researcher reading a 19th-century equity opinion who encounters "confidence" should read it as signaling a fiduciary or trust relationship, not a party's subjective conviction.
---
Common Confusion
Confidence and trust are not interchangeable in all legal contexts, even though historical sources treat them as nearly synonymous. Trust has a precise technical meaning in property law — a fiduciary arrangement with identifiable parties, res, and beneficial interest. Confidence is the broader equitable concept from which trust descends; not every relationship of confidence generates a technical express trust, but it may generate constructive or resulting trust obligations, or an independent equitable duty of confidentiality. Researchers conflating the two may overlook cases decided on confidentiality grounds that do not fit the formal trust framework.
---
Why It Matters in Research
Two distinct research threads run under this single word, and confusing them produces missed results.
The trust-as-confidence thread is primarily a wills and equity research problem. Before the consolidation of equity courts in the 19th century, courts of chancery regularly enforced obligations phrased in terms of "confidence" without the word "trust" appearing. Researchers searching for trust construction cases using only the word "trust" will miss decisions where the court's analysis hinges on the word "confidence." This is especially acute in English Chancery records and early American equity reports. The California and Pennsylvania citations in the historical sources reflect how this principle migrated into American case law.
The breach-of-confidence thread connects to trade secret law, professional privilege, and information law. Modern U.S. practice tends to analyze unauthorized disclosure of proprietary information under trade secret misappropriation doctrine (including the Uniform Trade Secrets Act and the Defend Trade Secrets Act), while English and Commonwealth courts developed breach of confidence as a stand-alone equitable action with broader reach. Researchers working on comparative IP questions, or on pre-UTSA American cases, need to track both doctrinal streams. The Law Mind Intellectual Property Encyclopedia entry on trade secret misappropriation addresses the overlap directly.
Historians of equity and trust law should also note that "confidence" language in older instruments was often deliberately chosen to avoid the technical formalities associated with declaring an express trust, while still invoking equitable intervention. Courts treated it as sufficient to create equitable obligations without necessarily creating a legal trust in the modern property-law sense.
---
Historical Dictionary Support
The historical sources converge on the trust-as-confidence equation without dissent. Black's (both editions) and Bouvier agree that in will construction, confidence is "peculiarly appropriate" to create a trust and is "as nearly a synonym as the English language is capable of." Bouvier's formulation — "trust is a confidence which one man reposes in another, and confidence is a trust" — captures the reciprocal definition that dominated 19th-century equity thinking.
Anderson's entry is characteristically sparse, redirecting to related terms (COMMUNICATION, CREDIT, FAITH, FIDUCIARY, TRUST, USE) rather than offering a definition, which itself is instructive: the word was understood to function as part of a network of equitable concepts rather than standing alone.
What the historical dictionaries do not address is the breach-of-confidence action as an independent equitable cause of action governing information. That doctrine developed more fully in English courts in the mid-20th century and has no real presence in these 19th-century American sources. Researchers relying solely on these dictionaries for information-law questions will need to supplement with treatises on equity and intellectual property.
---
Jurisdictional Note
In the United States, the breach-of-confidence action has largely been absorbed into trade secret law and professional privilege doctrines, and its independent equitable status varies by jurisdiction. In England, Australia, and other Commonwealth jurisdictions, breach of confidence remains a distinct and robust cause of action with broader coverage than statutory trade secret protection. Researchers working across these systems should not assume that U.S. trade secret case law translates directly into Commonwealth breach-of-confidence analysis.
---
Encyclopedia Cross-Reference
Trade Secret Misappropriation — Improper Means and Breach of Confidence (Law Mind Intellectual Property Encyclopedia) — addresses the overlap between equitable breach-of-confidence doctrine and statutory trade secret misappropriation claims, including how "improper means" analysis intersects with confidentiality obligations.
---