English edit

English numbers (edit)
 ←  17 18 19  → 
    Cardinal: eighteen
    Ordinal: eighteenth
    Adverbial: eighteen times
    Multiplier: eighteenfold
    Group collective: eighteensome

Etymology edit

eighteen +‎ -fold

Adjective edit

eighteenfold (not comparable)

  1. By a factor of eighteen.

Adverb edit

eighteenfold (not comparable)

  1. By a factor of eighteen.