DCXX

DCXX is the Roman numeral representation of the number 620. It is formed from the letters D, C, and XX, where D equals 500, C equals 100, and XX equals 20. When combined, DCXX denotes the value 620 in additive Roman numeral notation.

In historical dating, DCXX would denote the year 620 in the Common Era (620 CE) if used without further qualifiers. If a BCE designation is intended, the year would normally be specified as 620 BCE rather than as DCXX alone, to avoid ambiguity. In inscriptions, clocks, and chronologies, DCXX appears as a compact form for 620.

The numeral follows the standard rule of writing values in descending order from left to right, and there is no subtractive pair in DCXX (unlike CD for 400 or XC for 90).

Beyond pure numbers, DCXX may appear as part of identifiers, such as catalog numbers, model names, or section marks in documents, where it serves as an unambiguous label derived from Roman numerals. Its use in such contexts is typically associative with value rather than carrying an independent linguistic meaning.

See also: Roman numerals; Year numbering in the Julian and Gregorian calendars.