Numerical means expressed in numbers or relating to numbers. When you give a numerical answer in math class, you write “42” instead of “forty-two.” When a teacher asks for a numerical order, she wants things arranged by their numbers: 1, 2, 3, 4, and so on.

A numerical code uses numbers instead of letters, like a combination lock that opens with 15-27-8. Weather forecasts include numerical data: temperatures in degrees, rainfall in inches, wind speed in miles per hour. Scientists rely heavily on numerical measurements because numbers provide precise information that everyone can understand the same way.

The word helps distinguish between things measured with numbers versus described with words. If someone asks “How was your day?” and you say “great,” that's a descriptive answer. If you say “I scored 9 out of 10 on my spelling test,” that's numerical. Baseball statistics are numerical: batting averages, home runs, strikeouts. Your feelings about the game are not.

The opposite of numerical might be alphabetical (arranged by letters) or qualitative (described with words and qualities rather than measured with numbers).