Definition
In legal usage, "similar" carries an inherent ambiguity that courts have long been forced to resolve by context. It may mean either:
1. Partially resembling — sharing some but not all material characteristics; or
2. Identical in all essential particulars — effectively synonymous with "same in kind."
The word appears throughout statutes, rules of evidence, and contracts, and its operative meaning in any given instance depends heavily on the surrounding language, the legal purpose being served, and the jurisdiction's interpretive precedents. A statute enhancing penalties for a "previous conviction of a similar offense," for example, may be read to require an offense identical in kind rather than merely one that shares surface characteristics with the charged crime.
Common Language
Modern common usage (Wiktionary): "That which is similar to, or resembles, something else, as in quality, form, etc."
Historical common usage (Webster's 1913): "Nearly corresponding; resembling in many respects; somewhat like; having a general likeness." (Webster's also recognized a stronger meaning — "exactly corresponding; resembling in all respects; precisely like" — reflecting the word's inherent range.)
The gap matters: In ordinary English, "similar" almost always implies partial resemblance and is understood to fall short of identity. In legal instruments, courts have repeatedly held that "similar" can carry the stronger meaning of sameness in all essential particulars. A researcher who imports the common assumption that "similar" merely means "somewhat alike" may misread a statute, jury instruction, or contractual standard-of-care clause that a court has construed to demand essential identity.
Common Confusion
"Similar" is frequently conflated with "same," "identical," "like," and "analogous" in both drafting and judicial interpretation. These terms are not interchangeable in law. "Identical" generally requires complete correspondence; "like" often functions as a synonym for "similar" but may carry narrower connotations in tax and regulatory contexts (as in "like-kind exchange"); "analogous" is typically reserved for reasoning by comparison rather than factual or categorical resemblance. "Similar" sits in contested middle ground between partial and complete resemblance, which is the source of most interpretive disputes in which the word appears.
Why It Matters in Research
The central research trap with "similar" is that it appears deceptively simple — a common word with an obvious meaning — and researchers may not flag it as a term requiring interpretive scrutiny. In fact, it is one of the more context-dependent words in legal instruments, and its meaning has been litigated across evidence law, criminal sentencing, insurance policy construction, trademark, and contract interpretation.
In evidence law, "similar acts" or "similar transactions" evidence is a distinct doctrine with its own admissibility framework. Researchers working with rules of evidence must not conflate the evidentiary doctrine governing similar-acts evidence with the plain-language question of whether two things resemble each other.
In criminal law, "similar offense" provisions in recidivist statutes have generated substantial case law on whether the prior offense must be categorically identical or merely share essential elements. Older case law may apply a more expansive reading than modern categorical-approach doctrine permits.
Historical sources use "similar" without systematic definition, which means the same word may be construed differently across cases from the same era. When tracking a statutory phrase containing "similar" across time, check not just the word but the judicial gloss applied in each period.
In insurance and contract contexts, "similar" often appears in exclusion clauses and limitation-of-liability provisions. Courts in different jurisdictions apply varying presumptions — some favor the insured's or non-drafting party's reasonable interpretation (partial resemblance), others defer to industry usage that may demand stronger correspondence.
Anderson's Dictionary flags an important distinction for counterfeit-money statutes: "similar" is not equivalent to "in the similitude of," a phrase drawn from older federal coinage law. Researchers working in currency or forgery contexts should treat these as distinct terms.
Historical Dictionary Support
All four source dictionaries converge on the same core formulation: "similar" denotes either partial resemblance or sameness in all essential particulars. This agreement is itself informative — it confirms that the word's ambiguity was recognized at the time these dictionaries were compiled and was not resolved in favor of either meaning as a default.
Black's (both editions) and Bouvier's each anchor the stronger interpretation to Commonwealth v. Fontain, 127 Mass. 454, in which "previous conviction of a similar offense" was construed to mean conviction of an offense identical in kind. This is the only case cited across all sources, which means the historical dictionaries are drawing on a narrow judicial base. Researchers should not treat that single case as resolving the interpretive question generally — it is a Massachusetts decision on a specific statutory phrase.
Anderson's Dictionary adds a cross-reference to the Latin "similis" and to the distinct phrase "in similitudine," pointing toward the older common-law vocabulary from which "similar" partially derives. This is useful for researchers tracing the word's application in pre-twentieth-century statutes or English legal sources, where the Latin forms may appear alongside or instead of the English word.
What the historical dictionaries do not address: evidentiary doctrine governing similar-acts evidence, which developed substantially in the twentieth century; trademark and trade-dress similarity standards; and the categorical approach to prior-offense classification, which has reshaped how "similar offense" provisions are construed in federal criminal law.
Jurisdictional Note
Federal courts applying the categorical approach to recidivist sentencing have developed a specific methodology for determining whether a prior offense is "similar" to a current charge that does not map neatly onto the broader common-law ambiguity the dictionaries describe. State courts vary considerably, with some applying an elements-based test and others permitting broader factual inquiry. In insurance law, "similar" in policy exclusions is typically construed against the insurer in most jurisdictions, which may produce a narrower (partial-resemblance) reading even where the insurer intends a broader one.
Encyclopedia Cross-Reference
Law Mind Encyclopedia — Relevance and Admissibility of Evidence
Law Mind Encyclopedia — Prior Convictions and Recidivist Sentencing
Law Mind Encyclopedia — Insurance Policy Interpretation