A decimal point is a small dot used in writing a decimal fraction or a mixed number.
Notice that in a decimal fraction, 0 is usually placed before the decimal point.
In a mixed number, the decimal point separates the whole number part from the fractional part.
In a decimal fraction, we don't read the zero on the left of the decimal point.
We read 0.6 as six tenths
We read 0.007 as seven thousandths
We read 0.17 as seventeen hundredths
In a mixed number, the decimal point is read as "and" and we do read the number on the left of the decimal point.
We read 4.6 as four and six tenths
We read 9.007 as nine and seven thousandths
We read 20.17 as twenty and seventeen hundredths