The particle one of Singapore English is widely used in Singapore culture, but it is little mentioned and its invariant meaning has not been described, so that not much is known about its meaning and the cultural norms it reflects. This article provides a detailed semantic analysis of this particle, articulates its meaning in the form of a reductive paraphrase using natural semantic metalanguage, and argues that its use reflects Singapore English speakers' tendency to speak definitively and exaggeratedly. The discussion of Singaporean speech norms reflected by this particle includes reference to relevant Anglo English speech norms for comparison and contrast.I am indebted to Anna Wierzbicka for her detailed comments on an earlier version of this article. I am grateful to Jane Hill, Peter Tan and another, anonymous reviewer for their very generous and constructive overall feedback on this paper. I have also benefited from stimulating discussions with Cynthia Allen and Avery Andrews on the topic of relative clauses and the syntax of the nominal one. Jane McGary provided valuable editorial assistance and native Anglo English speaker intuition in regard to some examples. Last but not least, I would like to express my gratitude toward writer Hwee Hwee Tan for giving me a soft copy of her manuscript to do electronic searches.