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.
About This Tool. The online Roman Numerals Converter is used to convert Roman numerals to Hindu-Arabic numerals or vice versa. Roman numerals stem from the numeral system of ancient Rome. For example, 2016 in roman numerals is MMXVI and 2015 in roman numerals is MMXV. The first ten Roman numerals are I, II, III, IV, V, VI, VII, VIII, IX, and X. The following is the list of roman numerals from 1 to 1000: