Delimiter

A delimiter is the boundary marker between fields in a flat text file. The comma in CSV and the tab in TSV are the common ones, but semicolons and pipes (|) are also widely used, the semicolon especially in European locales where the comma is already the decimal separator.

Delimiter mismatches are one of the most common data-import failures. If a file is semicolon-delimited but a tool assumes commas, every row collapses into a single column. A robust parser detects the delimiter from the data rather than assuming one, which is why a file that 'won't open right' in one tool often loads cleanly in another.