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

It is not to be confused are "combining minus below" [[̠|]] (U+0320), "combining low line

Underline

An underline, also called an underscore, is one or more horizontal lines immediately below a portion of writing. Single, and occasionally double , underlining was originally used in hand-written or typewritten documents to emphasise text...

" (U+0332) and "low line" ("underscore

Underscore

The underscore [ _ ] is a character that originally appeared on the typewriter and was primarily used to underline words...

") _ ). The difference between "macron below" and "low line" is that the latter will result in an unbroken underline when run together, compare vs. .

Note that the Unicode names of composed characters whose decompositions contain this character misleadingly have "line below" rather than "macron below". Thus, ḇ "Latin small letter b with line below" decomposes to "Latin small letter b" and "combining macron below".

Precomposed characters

Unicode has a number of precomposed character

Precomposed character

A precomposed character is a Unicode entity that can be defined as a combination of two or more other characters. A precomposed character may typically represent a letter with a diacritical mark, such as é...

s with "macron below".

Ḇḇ, Ḏḏ, ẖ, Ḵḵ, Ḻḻ, Ṉṉ, Ṟṟ, Ṯṯ.

(minuscule: ) is used, for example, in the transliteration of Biblical Hebrew into the Roman alphabet to show the fricative

Fricative consonant

Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate, in the case of German , the final consonant of Bach; or...

 value of the letter beth

Bet (letter)

Bet, Beth, Beh, or Vet is the second letter of many Semitic abjads, including Arabic alphabet , Aramaic, Hebrew , Phoenician and Syriac...

 (ב). representing β. In Unicode the capital Ḇ is codepoint U+1E06 (7686) and the lower case ḇ is U+1E07 (7687). (minuscule: ) is used, for example, in the transliteration of Biblical Hebrew into the Roman alphabet to show the fricative

Fricative consonant

Fricatives are consonants produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate, in the case of German , the final consonant of Bach; or...

 value of the letter dalet

Dalet

Dalet is the fourth letter of many Semitic alphabets, including Phoenician, Aramaic, Hebrew , Syriac and Arabic...

 (ד), ð.

• is sometimes used for Arabic خ , Hebrew Heth (letter)
  Heth (letter)
  ' or ' is the reconstructed name of the eighth letter of the Proto-Canaanite alphabet, continued in descended Semitic alphabets as Phoenician , Syriac , Hebrew ḥēth , Arabic , and Berber .Heth originally represented a voiceless fricative, either pharyngeal , or...
  
  , 𓄡 second-uniliteral-ẖ Egyptian hieroglyph. Unicode "Latin small letter h with line below" is canonically equivalent to (U+0068 U+0331). Note that Unicode
  Unicode
  Unicode is a computing industry standard for the consistent encoding, representation and handling of text expressed in most of the world's writing systems...
  
   does not reserve a codepoint for a "Latin capital letter H with line below". Therefore, a sequence with a combining diacritic "[[̱|macron below]]" must be employed: (U+0048 U+0331). (minuscule: ) is one possible transliteration
  Transliteration
  Transliteration is a subset of the science of hermeneutics. It is a form of translation, and is the practice of converting a text from one script into another...
  
   of the Tamil
  Tamil script
  The Tamil script is a script that is used to write the Tamil language as well as other minority languages such as Badaga, Irulas, and Paniya...
  
   letter . is used in the Seri language
  Seri language
  Seri is a language isolate spoken by the Seri people by between 716 and 900 people in two villages on the coast of Sonora, Mexico.-Classification:...
  
   to represent l, like English l, while unmodified "l" represents ɬ, like Welsh ll. It is also used in the proposed Unified Alphabet for Mapudungun language. (minuscule: ) is used in Pitjantjatjara to represent ɳ, and in Saanich to represent both plain and glottalized
  Glottalization
  Glottalization is the complete or partial closure of the glottis during the articulation of another sound. Glottalization of vowels and other sonorants is most often realized as creaky voice...
  
   ɴ. (minuscule: ) is used in the proposed Unified Alphabet for Mapudungun language representing t̪.