Definition
A written question (or set of written questions) that one party to a lawsuit formally submits to another party or, in some contexts, to a witness, requiring a written answer under oath. Interrogatories are a standard tool of pretrial discovery in civil litigation, governed by court rules that specify their form, timing, and limits.
In modern federal practice, interrogatories are directed only to parties, not to non-party witnesses (who are instead examined by deposition). A responding party must answer each interrogatory fully and in writing, under oath, or state a specific objection with grounds. Answers become part of the discovery record and may be used at trial to impeach or bind the responding party.
Common Language
Modern common usage (Wiktionary): A formal question or set of questions submitted to an opposing party to answer, generally governed by court rule; also, more generally, any question or interrogation.
Historical common usage (Webster's 1913): A formal question or inquiry; especially (Law) a question asked in writing.
The common usage is close but incomplete. Ordinary usage captures the written-question form but misses the procedural machinery: interrogatories in modern civil practice are strictly party-to-party instruments with mandatory sworn responses, objection rules, and numerical limits. The general sense of "a formal question" describes their surface form, not their legal function.
Common Confusion
Interrogatories are sometimes confused with deposition questions because both involve questioning under oath during discovery. The distinction matters: interrogatories are written questions answered in writing, at leisure, typically with attorney assistance in drafting responses; depositions are oral examinations in real time before a court reporter. Interrogatories are also sometimes loosely confused with requests for admission, which ask a party to admit or deny specific facts rather than to answer open-ended questions. Each device serves a different strategic purpose, and courts treat them as distinct procedural instruments.
Why It Matters in Research
Researchers working in the Law Mind corpus encounter two substantially different regimes depending on the era of the source.
Before the Federal Rules of Civil Procedure (1938), interrogatories in American equity practice functioned differently from their common-law counterparts, and the two tracks ran in parallel. In equity, interrogatories were the primary mechanism for examining parties — a party could be compelled to answer written questions as part of the bill of complaint process. At common law, parties were generally not competent witnesses and could not be examined by interrogatory in the same way; that gap was partly filled by the bill of discovery in equity. Sources predating 1938 will reflect this split-system world, and a researcher finding references to "interrogatories to a party" in a pre-1938 source should not assume modern discovery practice is being described.
Post-1938, federal interrogatories became a unified pretrial discovery device available in all civil actions. Successive amendments to Federal Rule of Civil Procedure 33 progressively tightened the rules: numerical limits (now 25 interrogatories absent court order or stipulation), contention interrogatory timing, and the option to produce business records in lieu of a narrative answer. Research into discovery disputes from different eras must account for which version of Rule 33 was operative.
Jurisdictional variation is a persistent trap. State courts often impose different numerical limits, different response periods, and different standards for when interrogatories may be used. A researcher generalizing from federal practice to state-court sources (or vice versa) risks misreading procedural history.
Finally, the distinction between direct interrogatories and cross-interrogatories — prominent in the historical sources — surfaces frequently in older cases involving out-of-court examination of witnesses under commission, a practice now largely replaced by depositions on written questions under modern rules.
Historical Dictionary Support
Anderson and Burrill both anchor their definitions in the equity and commission-examination tradition that predates unified civil procedure. Anderson's treatment is structurally useful: it distinguishes direct (or original) interrogatories, posed by the party calling the witness, from counter or cross-interrogatories, posed by the adverse party. This terminology maps onto the commission-examination procedure, in which witnesses examined outside the courtroom (often in another jurisdiction or country) were questioned through pre-drafted written sets. The phrase "fishing interrogatory" appears in Anderson, reflecting the period concern — still alive in modern practice — about interrogatories used to embark on speculative searches for evidence rather than to obtain specific known information.
Burrill's entry reinforces the same frame, emphasizing that interrogatories were "sets of questions in writing drawn up according to a certain form" for use in examination out of court. Both sources treat interrogatories primarily as an equity-and-commission device rather than as a general litigation tool available in all civil cases — a limitation that reflects pre-1938 reality.
What the historical sources do not address: the modern numerical limits, the business-records option, contention interrogatories, or the party-only restriction of modern federal practice. Researchers should treat these entries as accurate for their era while recognizing they describe a procedural landscape that was substantially reorganized in the twentieth century.
Jurisdictional Note
Federal practice limits interrogatories to 25 per party absent leave of court or stipulation (FRCP 33). State courts vary widely — some impose lower limits, some higher, and some require leave of court before any interrogatories may be served. A few states continue to permit interrogatories directed to non-parties in limited circumstances, diverging from the federal party-only rule.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Discovery; Civil Procedure; Bill of Discovery (Equity Practice).