Roman religious vocabulary for the dead was considerably more layered than a single word for "ghost," and understanding the lemures requires placing them against the two other categories they were explicitly contrasted with: the di manes, the more general and often honoured collective spirits of the dead invoked on tombstones and in state cult, and the lares, protective household and ancestral spirits actively venerated at a shrine within the home, the lararium, as sources of ongoing blessing.
Some Roman writers, including Ovid, note that ancient usage occasionally treated lemures and manes as broadly overlapping terms for the same dead viewed from different angles, benevolent when properly honoured as manes or lares, dangerous and unappeased when acting as lemures, rather than as populations of entirely different beings. This three-part vocabulary, threatening lemures, generalised manes, and cultivated lares, gave Roman domestic religion a complete working theology of the dead's ongoing presence in the household, one in which ritual maintenance rather than a single funeral determined whether a family's dead remained a blessing or became a hazard.