The word 'ph' appears to have a typo or may be an abbreviation. In the context of education or chemistry, 'pH' refers to a scale used to measure how acidic or basic a solution is. A pH of 7 is neutral, below 7 indicates acidity, and above 7 indicates alkalinity.
The term pH was created in the late 19th century. The 'p' stands for 'potenz' in German, meaning power, and 'H' represents hydrogen. The concept was developed by the Danish chemist Søren Sørensen in 1909.