one-sixth vs sixth

one-sixth

• One of six equal parts (1/6, ⅙, 0.1666…). 

sixth

• One of six equal parts of a whole. 

• The interval between one note and another, five notes higher in the scale, for example C to A, a major sixth, or C to A flat, a minor sixth. (Note that the interval covers six notes counting inclusively, for example C-D-E-F-G-A.) 

• The person or thing in the sixth position. 

• The ordinal form of the number six. 

• to divide by six, which also means multiplying a denominator by six