- -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. [1913 Webster]
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. [1913 Webster]
The Collaborative International Dictionary of English. 2000.