from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An inexperienced or immature person, especially one who is easily deceived.
- n. A newcomer, especially one who is unfamiliar with the ways of a place or group.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. an inexperienced person; a novice, beginner or newcomer
from the GNU version of the Collaborative International Dictionary of English
- n. A raw, inexperienced person; one easily imposed upon.
from The Century Dictionary and Cyclopedia
- n. A raw, inexperienced person; one unacquainted with the world or with local customs, and therefore easily imposed upon.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an awkward and inexperienced youth
Middle English greene horn, horn of a newly slaughtered animal : grene, green; see green + horn, horn; see horn.(American Heritage® Dictionary of the English Language, Fourth Edition)
Unconfirmed. Hypotheses include: (Wiktionary)