Monomane

Part of speech: noun

Definitions

1. A mental state exemplified by an intense fixation on one single concept or theme, indicating an obsessive preoccupation with a specific idea or belief
2. This condition highlights a person's extreme dedication to a solitary interest, often at the expense of broader perspectives
3. A state characterized by an overwhelming concentration on just one particular idea or subject

Etymology: Monomania comes to English from French "monomanie", and the French word is built from two Greek pieces: "monos", meaning single or alone, and "mania", meaning madness or frenzy. Put together, the term describes a mind stuck on one subject, a madness confined to a single track rather than spreading across the whole personality. The second half, "-mane" in the source's form, is the same Greek root that gives English words like "maniac" and "mania" itself, so the family resemblance is direct. The "mono-" prefix is the familiar one from "monorail" or "monologue", which tells you the core idea at a glance: one thing, to the exclusion of everything else.