Definition of siglum in US English:

siglum

noun

  • A letter (especially an initial) or other symbol used to denote a word in a book, especially to refer to a particular text.

    • ‘The Wake's hybridist nature extends beyond genre, even beyond portmanteau words, indeed to the most atomic level of text (letters, punctuation, sigla of all forms).’
    • ‘The equal sign used here stands for a three-lined equal sign in the book, but my computer cannot produce such a siglum.’

Origin

Early 18th century: from late Latin sigla (plural), perhaps from singula, neuter plural of singulus ‘single’.

Pronunciation

siglum

/ˈsiɡləm/