A person briefly cannot recall the name of a familiar acquaintance during a conversation, experiencing a strong sense that the name is known and almost within reach, before it resolves on its own moments later with no lasting difficulty. What is this?

This is lethologia: a temporary inability to retrieve a specific name or proper noun despite otherwise intact knowledge, often accompanied by the classic "tip of the tongue" feeling, resolving on its own without any lasting difficulty, exactly as described. It is not nominal aphasia, in which name-finding difficulty is persistent, pervasive, and part of a broader language disturbance, rather than this brief, isolated, and self-resolving lapse. It is not amnesia, since knowledge of the person and the situation is otherwise fully intact, with only the specific name briefly inaccessible, not a broader gap in recall. And it is not dementia, since lethologia occurs in the general population and is not, on its own, indicative of any pathology at all.