One purpose of this column, "Stand on Standards," is to discuss antenna and propagation terms of controversy, with a goal of soliciting comments for the Subcommittees on Definitions, which are working toward standardized definitions. As noted in my column on fading (in the August, 1992, issue of the Magazine), this can be rather dry and tedious work which is not of great general interest. While this particular column may be of most interest to only a relatively small (and aging?) percentage of the Magazine's readership, it is an attempted start at cleaning up some old business that is receiving renewed attention, internationally. Despite continuing rumors of its demise, HF has exhibited great longevity, since its first use just after the turn of the century. This is true even though satellites and modern cables have largely replaced it as the primary medium for long-distance communication, in most cases. Therefore, please bear with me, as we revisit the definition of MUFs and LUFs, MOFs and LOFs, and related terms.