The Collaborative International Dictionary of English v.0.48:

Learner \Learn"er\, n.
   One who learns; a scholar.
   [1913 Webster]

WordNet (r) 3.0 (2006):

learner
    n 1: someone (especially a child) who learns (as from a teacher)
         or takes up knowledge or beliefs [syn: learner,
         scholar, assimilator]
    2: works for an expert to learn a trade [syn: apprentice,
       learner, prentice]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "learner":
   abecedarian, apprentice, auditor, autodidact, baby, beginner,
   catechumen, deb, debutant, educatee, entrant, fledgling, freshman,
   greenhorn, greeny, infant, initiate, inquirer, monitor, neophyte,
   nestling, newcomer, novice, novitiate, praepostor, prefect,
   probationer, pupil, raw recruit, recruit, rookie, scholar,
   self-taught person, student, studier, tenderfoot, trainee, tyro