Definition of "IQ"

A ratio scale is one with an absolute zero and equal intervals between the units of the scale. Height and weight are such scales. Presumably IQ is not, and certainly the Fahrenheit and centigrade scores are not.

1987, Roger R. Flynn, “[Data Organization and Use] Understanding the Data”, in An Introduction to Information Science, Marcel Dekker, Inc., page 129

Not everyone is quite as enamoured with IQ tests as Trump. In 2004, the New York Times asked Stephen Hawking what his IQ was and he memorably replied: “People who boast about their IQ are losers.”

2017 December 10, Arwa Mahdawi, “Having a high IQ is a curse … just look at Donald Trump”, in The Guardian‎