semitone -
UK, Ireland, Australia, New Zealand The musical interval equal exactly or approximately to half a tone or one-twelfth of an octave.
semitone -
UK, Ireland, Australia, New Zealand Any of the pitches of the chromaticscale.
Wikipedia
A semitone, also called a half step or a half tone,Aaron Copland, Leonard Bernstein, and others use "half tone". http://books. google. com/books?id=dsyPycO3GfgC&pg=PA41&vq=the+twelve+chromatic+ones,+arranged+in+the+following+order:+two+whole+tones+followed+by+a+half+tone,+plus+three+whole+tones+followed+by+a+half+tone. &source=gbs_search_r&cad=1_1&sig=ACfU3U2YEr33cdQqp6Q1U0Um69XF4BU5pQ http://books. google.