zone fossil typically occurs fewer than 0.01 times per million words in modern written English.
zone fossil is in frequency band 2, which contains words occurring between 0.001 and 0.01 times per million words in modern written English. More about OED's frequency bands
Frequency data is computed programmatically, and should be regarded as an estimate.
Frequency of zone fossil, n., 1900–2010
* Occurrences per million words in written English
Historical frequency series are derived from Google Books Ngrams (version 2), a data set based on the Google Books corpus of several million books printed in English between 1500 and 2010.
The overall frequency for a given word is calculated by summing frequencies for the main form of the word, any plural or inflected forms, and any major spelling variations.
For sets of homographs (distinct entries that share the same word-form, e.g. mole, n.¹, mole, n.², mole, n.³, etc.), we have estimated the frequency of each homograph entry as a fraction of the total Ngrams frequency for the word-form. This may result in inaccuracies.
Smoothing has been applied to series for lower-frequency words, using a moving-average algorithm. This reduces short-term fluctuations, which may be produced by variability in the content of the Google Books corpus.
Decade
Frequency per million words
1900
0.0067
1910
0.0069
1920
0.0081
1930
0.0086
1940
0.0096
1950
0.01
1960
0.0096
1970
0.0078
1980
0.0072
1990
0.006
2000
0.0048
2010
0.004
Originally published as part of the entry for zone, n.
zone, n. was first published in 1921; not fully revised.