Definition
To opt means to make a deliberate choice between available alternatives, particularly in a legal or contractual context. The term appears most frequently in compound constructions that carry distinct legal significance:
1. Opt in: To affirmatively elect to participate in a scheme, program, agreement, or class action. Participation requires a positive act; silence or inaction does not constitute opting in.
2. Opt out: To affirmatively elect to withdraw from, or decline participation in, a scheme, program, agreement, or class action. In many consumer protection and class action contexts, the default is inclusion unless a party takes affirmative steps to opt out.
3. Opt-in/opt-out regime: A regulatory or contractual framework that structures default participation and the mechanism by which a party may depart from that default.
Common Language
Modern common usage (Wiktionary): Listed primarily as an abbreviation for Old Portuguese; general verb usage ("to opt") means simply to make a choice or decision.
Historical common usage (Webster's 1913): Not independently listed as a legal term; treated as a general English verb meaning to choose or select, derived from the Latin optare.
The gap between common and legal meaning here is structural rather than semantic. In ordinary English, "to opt" is simply to choose. In legal contexts, opting in or out carries procedural consequence: it determines whether a binding agreement, class membership, or regulatory obligation attaches. The act of opting — or failing to opt — can be as consequential as signing a contract.
Common Confusion
Opt in and opt out are often treated as interchangeable, but the distinction is legally critical. An opt-in regime requires affirmative consent before obligations or benefits attach; silence equals non-participation. An opt-out regime presumes participation and requires affirmative action to exit; silence equals inclusion. Conflating the two can lead to serious errors when analyzing consumer consent frameworks, class action notices, or data privacy regulations.
Core Elements
For the choice to constitute a legally effective opt-in or opt-out, courts and regulators generally look to:
1. Notice: The party must have received adequate notice of the choice available and its consequences.
2. Opportunity: A meaningful window and mechanism must exist for exercising the election.
3. Affirmative act or inaction (context-dependent): Depending on the regime, opting may require a positive act (checking a box, returning a form, filing a notice) or may be triggered by the absence of any act within a defined period.
4. Capacity and voluntariness: As with any election, the choosing party must have had legal capacity and not have been subject to coercion or misrepresentation.
Why It Matters in Research
Researchers working with historical sources should approach "opt" carefully. As a legal term of art, "opt in" and "opt out" are largely creatures of twentieth- and twenty-first-century law. They emerged prominently in U.S. consumer protection statutes, class action procedure (particularly after the Federal Rules of Civil Procedure were amended and interpreted through cases addressing Rule 23), and later in data privacy legislation. Searching older digests and legal encyclopedias for "opt" as a standalone legal concept will yield little; researchers must trace the doctrine through related terms: election, consent, waiver, class action, and notice.
In the modern corpus, "opt out" carries particular weight in two clusters: (1) class action litigation, where the right of class members to opt out of a settlement or judgment is a due process requirement in certain class types; and (2) consumer and privacy law, where opt-in and opt-out regimes define the baseline of permissible data use, marketing contact, and arbitration clause enforcement.
Jurisdictional and regulatory variation is substantial. Federal statutes, state consumer protection laws, and international frameworks (notably the EU's GDPR, which generally imposes an opt-in standard for data consent) differ significantly. Researchers should not assume that a finding about opt-out rights under one regime transfers to another.
Historical sources in the Law Mind corpus that use the verb "open" in procedural contexts — as Burrill's entry illustrates — are not precursors to "opt" in its modern legal sense. The Burrill entry catalogued here pertains to opening argument and opening a case, entirely unrelated to the opt-in/opt-out doctrine. Researchers should not treat proximity of terms in older alphabetically arranged dictionaries as indicating conceptual relationship.
Historical Dictionary Support
Burrill's Law Dictionary does not contain a standalone entry for "opt" in the modern legal sense. The entry retrieved in source material addresses "open" in procedural usage — specifically, counsel opening a case to the jury — and references Roman law usage of oportet (what is necessary or obligatory). This is not a cognate concept. The absence of "opt" as a legal term in Burrill reflects the historical reality that opt-in and opt-out as legal constructs postdate the classical period of English and American common law lexicography. Researchers relying on nineteenth-century dictionaries for this concept will find nothing useful and should proceed directly to twentieth-century statutory and regulatory sources.
Jurisdictional Note
The legal significance of opting in versus opting out varies considerably by context and jurisdiction. Federal class action procedure, the CAN-SPAM Act, TCPA consent frameworks, state data privacy statutes (California's CCPA, for example), and international privacy regimes each define opt-in and opt-out differently and with different default rules. Research should always identify the governing statute or rule before applying conclusions about one regime to another.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: CONTRACT FORMATION (for the role of affirmative consent and election); CONSUMER PROTECTION LAW (for opt-in and opt-out regulatory frameworks); CLASS ACTIONS (for due process requirements governing opt-out rights).