What's the difference between i.e. and e.g.?
"insanity in regard to a single subect or class of subjects," 1820, probably on model of earlier French monomanie, from Modern Latin monomania, from Greek monos "single, alone" (see mono-) + mania (see mania).
monomania mon·o·ma·ni·a (mŏn'ə-mā'nē-ə, -mān'yə)n. Pathological obsession with one idea or subject, as in paranoia.