Definition of "diatonic" [di•a•ton•ic]

• Music Of or using only the seven tones of a standard scale without chromatic alterations. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "There are many types of button accordions, usually with the buttons arranged in diatonic rows."
• "One genus was called the diatonic; one example of this is the Pythagorean diatonic described above, which is built on the tetrachord with the intervals 9: 8, 9: 8 and 256: 243 and was used by Philolaus and Plato."
• "Each speller and each reader went through the whole gamut of sounds, from low up to high, and from high down to low again; sometimes by regular ascension and descension, one note at a time, sounding what musicians call the diatonic intervals; at other times, going up and coming down upon the perfect fifths only."