noun (n)

• a plant that is found in an area where it had not been recorded previously(noun.plant)

  source: wordnet30
• any new participant in some activity(noun.person)

  Synonym:
  entrant, fledgeling, fledgling, freshman, newbie, newcomer, starter
  

  source: wordnet30
• a new convert being taught the principles of Christianity by a catechist(noun.person)

  Synonym:
  catechumen
  

  source: wordnet30
• A new convert or proselyte; -- a name given by the early Christians, and still given by the Roman Catholics, to such as have recently embraced the Christian faith, and been admitted to baptism, esp. to converts from heathenism or Judaism.(noun)

  source: webster1913