beginner

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One that begins.
• noun One who is just starting to learn or do something; a novice.

from The Century Dictionary.

• noun One who begins or originates; one who starts or first leads off; an author or originator.
• noun One beginning to learn or practise; a novice; a tyro: as, “a sermon of a new beginner,” Swift.

from the GNU version of the Collaborative International Dictionary of English.

• noun One who begins or originates anything. Specifically: A young or inexperienced practitioner or student; a tyro.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Someone who is just starting at something, or has only recently started.
• noun Someone who sets (or puts) something in motion

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a person who founds or establishes some institution
• noun someone new to a field or activity