What are commas?

Some articles on commas, comma:

Comma (music) - Other Intervals Called Commas
... There are also several intervals called commas, which are not technically commas because they are not rational fractions like those above, but are irrational approximations of them ... These include the Holdrian and Mercator's commas ...
Comma - Uses in English - Separation of Clauses
... Commas are often used to separate clauses ... In English, a comma is generally used to separate a dependent clause from the independent clause if the dependent clause comes first After I fed the cat, I brushed ... with I brushed my clothes after I fed the cat.) A relative clause takes commas if it is non-restrictive, as in I cut down all the trees, which were over six feet tall ...
Hungarian Orthography - Punctuation - Elements Wedged Into A Clause - Interposition
... (especially external elements) interposed into a sentence are marked with commas, dashes (with spaces), or parentheses ... ‘My brother, as the witness of the accident, was heard several times.’ The comma may be omitted around interposed elements depending on the articulation, reflecting the intention of the author, e.g ... ‘The train was, of course, late again.’ can be written without commas as well ...
Comma - Diacritical Usage
... The comma is used as a diacritic mark in Romanian under the s (Ș, ș), and under the t (Ț, ț) ... The symbol d̦ (d with comma below) was used as part of the Romanian transitional alphabet (19th century) to indicate the sounds denoted by the Latin letter z or ... The comma and the cedilla are both derivative of a small cursive z (ʒ) placed below the letter ...
Comma Operator - Syntax
... The comma operator separates expressions (which have value) in a way analogous to how the semicolon terminates statements, and sequences of expressions are enclosed in ... Note that a comma can only occur between two expressions – commas separate expressions – unlike the semicolon, occurs at the end of a (non-block) statement – semicolons ... The comma operator has the lowest precedence of any C operator, and acts as a sequence point ...