An alternative name for a power-law distribution, which emphasises the scale free property. That is, if you imagine zooming in or out of the graph of a power law it looks the same shape at every scale. In contrast, if you have a Normal distribution (or indeed many kinds of distribution) and you zoom out, the distribution gets more narrow and the mean looks closer to zero. At a practical level Normally distributed data, such as people's heights, have a natural scale.
Used in page 51
Links:
methods.sagepub.com:
Sampling Bias in SAGE: Encyclopedia of Survey Research Methods
Wikipedia:
Sampling Bias
scribbr.com:
Sampling bias: What is it and why does it matter?