PCO stands for Potential Change Order (construction management). Suggest new definition. This definition appears somewhat frequently and is found in the following Acronym Finder categories: 1  Business, finance, etc.
Quick Answer. The Roman numeral XIX is the number 19. X is the number 10, and I is the number one. When a lower number is placed in front of a larger number, it indicates subtraction; IX is the same as 10 minus one, which equals nine. The Ancient Romans used different letters to represent numbers.
These are some examples of Roman numerals: 1  The current year is 2016, and it is written as MMXVI with Roman Numeral symbols. 2  Time 12:00 with roman numerals must be written as XII.  Time 08:00 with roman numerals must be written as VIII.