The stratigraphic contexts (findspots) of artifacts from Sardis are recorded at different levels of specificity. Sector is the most general, referring to a broad area of the city. Trenches are yearly excavation areas (in current usage) or more specific areas of sectors (in early records which used a different excavation system). A Locus is a single stratigraphic unit, i.e. a single deposit of soil, a destruction level, a grave, a dump or other deposit. For instance, MMS-I 84.1 Locus 34 is the destruction level from one room of a Lydian house just inside the fortification wall in sector MMS, containing a rich deposit of Lydian pottery and other artifacts. Note that loci can be continued over a number of years, and so belong to different trenches, if the same stratigraphic unit is excavated over a number of years. For a list of sectors see Hanfmann and Waldbaum, A Survey of Sardis and the Major Monuments Outside the City Walls (Sardis R1, 1975), 13-16. Currently (2020) in order to search for a specific locus, you must search for Trench first to narrow the results, and then search within that for the locus. Sorry.