Definition of eighteenmo in US English:

eighteenmo

noun

  • another term for octodecimo
    • ‘Comparing his list of conger members with the Tillotson imprints shows that the conger also produced the folios of 1728 and the eighteenmo of 1748.’
    • ‘On the basis of the distribution of the watermarks the volume may be identified as an eighteenmo.’

Pronunciation

eighteenmo

/ˌeɪˈtinˌmoʊ//ˌāˈtēnˌmō/