en-

WordReference Random House Learner's Dictionary of American English © 2026

en-¹ ,prefix. 

1. en- is attached to adjectives or nouns to form verbs meaning:
   • to cause (a person or thing) to be in (the place, condition, or state mentioned);
     to keep in or place in:
     en- + rich → enrich (= to cause to be rich);
     en- + tomb → entomb (= to cause to be in a tomb)
     ;
     
   • to restrict on all sides, completely:
     en- + circle → encircle (= to restrict on all sides within a circle).

-en¹ ,suffix. 

1. -en is used to form verbs and adjectives.
   • It is attached to some adjectives to form verbs with the meaning "to be or make'':
     hard + -en → harden (= to be or make hard).
   • It is attached to some nouns to form verbs with the meaning "to add to, cause to be, or have'':
     length + -en → lengthen (= to add length to;
     make long).
2. It is attached to some nouns that are materials or sources of something to form adjectives that describe the source or material:
   gold + -en → golden (= like gold).

Collins Concise English Dictionary © HarperCollins Publishers::

en-, em- prefix:forming_verbs

1. (from nouns) put in or on: entomb, enthrone
2. go on or into: enplane
3. surround or cover with: enmesh
4. furnish with: empower
5. (from adjectives and nouns) cause to be in a certain condition: enable, encourage, enrich, enslave

Etymology: via Old French from Latin in- in-²

en-, em- prefix:forming_verbs

1. in; into; inside: endemic

Etymology: from Greek (often via Latin); compare in-¹, in-²