Definition of micromania in US English:

micromania

noun

Medicine
rare
  • The delusion that the body or part of it has become abnormally small. Also: a persistent or exaggerated tendency to belittle oneself or regard oneself as unimportant.

Origin

Late 19th century; earliest use found in The New Sydenham Society's Lexicon of Medicine and the Allied Sciences. From micro- + -mania.

Pronunciation

micromania

/mʌɪkrə(ʊ)ˈmeɪnɪə/