Macron below is a combining diacritical mark that is used in various orthographies.

A non-combining form is U+02CD ˍ MODIFIER LETTER LOW MACRON. It is not to be confused with U+0320 ◌̠ COMBINING MINUS SIGN BELOW, U+0332 ◌̲ COMBINING LOW LINE and U+005F _ LOW LINE. The difference between "macron below" and "low line" is that the latter results in an unbroken underline when it is run together: compare a̱ḇc̱ and a̲b̲c̲ (only the latter should look like abc).

Unicode defines several characters for the macron below:

There are many similar marks covered elsewhere:

Various precomposed letters with a macron below are defined in Unicode:

Note that the Unicode character names of precomposed characters whose decompositions contain U+0331 ◌̱ COMBINING MACRON BELOW use "WITH LINE BELOW" rather than "WITH MACRON BELOW". Thus, U+1E07 ḇ LATIN SMALL LETTER B WITH LINE BELOW decomposes to U+0062 b LATIN SMALL LETTER B and U+0331 ◌̱ COMBINING MACRON BELOW.

The Vietnamese đồng currency sign resembles a lower case d with a stroke and macron below: U+20AB ₫ DONG SIGN but is neither a letter nor decomposable.

In Swedish, o̱ is frequently used as a substitute for &, particularly in handwriting and in prose.