Definition of "fossil"

He draws eclectically on studies of baboons, descriptive anthropological accounts of hunter-gatherer societies and, in a few cases, the fossil record.

2012 March-April, John T. Jost, “Social Justice: Is It in Our Nature (and Our Future)?”, in American Scientist‎, volume 100, number 2, archived from the original on 13 February 2012, page 162

I do not want to convey any disrespectful notion or slight when I call those good and learned men fossils, but my experience is that people are apt to fossilise even at a University if they follow the same paths too persistently.

1886 October – 1887 January, H[enry] Rider Haggard, She: A History of Adventure, London: Longmans, Green, and Co., published 1887