Oneanaphora (e.g.,this is a good one) has been used as a key diagnostic in syntactic analyses of the English noun phrase, and “one‐replacement” has also figured prominently in debates about the learnability of language. However, much of this work has been based on faulty premises, as a few perceptive researchers, including Ray Jackendoff, have made clear. Abandoning the view of anaphoricone(a‐one) as a form of syntactic replacement allows us to take a fresh look at various uses of the wordone. In (...) the present work, we investigate its use as a cardinal number (1‐one) in order to better understand its anaphoric use. Like all cardinal numbers, 1‐onecan only quantify an individuated entity and provides an indefinite reading by default. Owing to unique combinatoric properties, cardinal numbers defy consistent classification as determiners, quantifiers, adjectives, or nouns. Once the semantics and distribution of cardinal numbers, including 1‐one, are appreciated, many properties ofa‐onefollow with minimal stipulation. We claim that 1‐oneanda‐oneare distinct but very closely related lexemes. When 1‐oneappears without a noun (e.g.,Takeone), it is nearly indistinguishable froma‐one(e.g.,takeone)—the only differences being interpretive (1‐oneforegrounds its cardinality whilea‐onedoes not) and prosodic (presence versus absence of primary accent). While we ultimately argue that a family of constructions is required to describe the full range of syntactic contexts in whichoneappears, the proposed network accounts for properties ofa‐oneby allowing it to inherit most of its syntactic and interpretive constraints from its historical predecessor, 1‐one. (shrink)