We propose a general nomenclature for discrete RNA structures that resist degradation by Xrn1. We refer to them as ‘Xrn1-resistant RNAs’ (xrRNAs), and we modify this term by including the name of the virus in which the xrRNA is found. When more than one xrRNA is present in a viral RNA, we propose numbering them sequentially. Thus, the 5′ most discrete Xrn1-resistant structure in the Dengue virus genome is named ‘DENV2xrRNA1.’ This nomenclature builds on and is consistent with existing nomenclature and has several advantages: Distinguishes between the discrete RNA structures that resist Xrn1 (xrRNAs) and the larger product of resistance that includes additional sequences of diverse function (sfRNAs). Provides a consistent convention across viral species and independent of idiosyncratic naming of putative secondary structure elements. Is consistent with the accepted practice of classifying and naming RNAs based on function. For example, IRES RNAs are often part of a larger 5′ UTR and may comprise a collection of secondary structural elements, but they are named as discrete functional entities within the 5′ UTR and are identified by their source (e.g., ‘HCV IRES RNA’). The term ‘xrRNA’, modified by source, follows this convention. Allows matching of the name of the xrRNA to the sfRNA it produces. For example, during Kunjin virus infection 4 putative sfRNAs are made (sfRNA1, sfRNA2, etc). With our proposed nomenclature, the name of the xrRNA structure logically corresponds to the product it makes (i.e., sfRNA1 is made by xRNA1, sfRNA2 by xrRNA2 etc). Because this naming convention is based on function and position, this nomenclature is readily extended to xrRNAs that could someday be found in contexts other than flaviviruses. Outline of the naming strategy we propose for Xrn1-Resistant RNAs and application to test RNAs in this study. (A) As shown, we propose a naming strategy that includes designations for an Xrn1-resistant RNA’s function, viral origin, position within in a FV 3′UTR and the presence upstream and downstream RNA sequences. (B) The secondary structure of (+31)-DVxrRNA1-MG illustrates how different components of this naming system apply to the test RNAs used in this study. (C) A stick diagram of the DENV 3′UTR shows how the number scheme we propose for xrRNAs applies to the presence of multiple xrRNAs within a single 3′UTR.