Source : Webster's Revised Unabridged Dictionary (1913)

-en \-en\
   1. A suffix from AS. -an, formerly used to form the plural of
      many nouns, as in ashen, eyen, oxen, all obs. except oxen.
      In some cases, such as children and brethren, it has been
      added to older plural forms.

   2. A suffix corresponding to AS. -en and -on, formerly used
      to form the plural of verbs, as in housen, escapen.

   3. A suffix signifying to make, to cause, used to form verbs
      from nouns and adjectives; as in strengthen, quicken,
      frighten. This must not be confused with -en corresponding
      in Old English to the AS. infinitive ending -an.

   4. [AS. -en; akin to Goth. -eins, L. -inus, Gr. ?.] An
      adjectival suffix, meaning made of; as in golden, leaden,
      wooden.

   5. [AS. -en; akin to Skr. -na.] The termination of the past
      participle of many strong verbs; as, in broken, gotten,
      trodden.