hemidemisemiquaver
NOTES: It’s a long word about the shortest note in music. For another example of prefixes gone wild, see preantepenultimate (fourth from the last).
ETYMOLOGY: From Greek hemi- (half) + French demi- (half) + Latin semi- (half) + quaver (an eighth note), from Middle English quaveren (to shake or tremble). Earliest documented use: 1853.
USAGE: “‘Commissaire, you have a foreigner’s ear for our glorious language. Their names are completely different, CAYO and CAYOo,’ Martiniere said, lingering the merest hemidemisemiquaver on the final imagined phoneme of the second ‘YO’.”
Alexander Campion; Killer Critique; Kensington; 2012.
See more usage examples of hemidemisemiquaver in Vocabulary.com’s dictionary.
Sixty-fourth note
In music notation, a sixty-fourth note (American), or hemidemisemiquaver or semidemisemiquaver (British) is a note played for half the duration of a thirty-second note (or demisemiquaver), hence the name.
It first occurs in the late 17th century and, apart from rare occurrences of hundred twenty-eighth notes (semihemidemisemiquavers) and two hundred fifty-sixth notes (demisemihemidemisemiquavers), it is the shortest value found in musical notation (Morehen 2001).
1936 photo by 
saywhatumean2say 