treble clef

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

• noun A symbol indicating that the second line from the bottom of a staff represents the pitch of G above middle C.

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

• noun music a symbol showing that the second line from the bottom of the stave represents the G above middle C

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

• noun a clef that puts the G above middle C on the second line of a staff