This essay describes the development of the word numeracy as it evolved from its initial use in 1959 to its current meaning today. Initially appearing in a British report to address mathematics education of teenage boys and girls, it was first used in relation to the word literate and defined as the ability with or knowledge of numbers. By the mid-1960s, the meaning shifted from computation of numbers to the ability to interpret data and make sense of the world through business, science, and technology. In the 1970s, numeracy was seen as a skill that was essential in life and by the turn of the twenty-first century, numeracy came to include the ability to reason. Numeracy was no longer seen simply in the area of mathematics but continued to permeate through all areas of study and furthermore, into daily life.