A plane (planen.3 1a) from or against which measurements or comparisons are made.
1842
Where v is the temperature at the time t, of a point at the distance x from a fixed plane, which, for brevity, may be called the zero plane.
Cambridge Mathematical Journalvol. 3 170
1880
The zero plane is the surface of the ellipsoid similar to the sea surface.
S. Haughton, Six Lectures on Physical Geography ii. 51
2015
Two coronal and two horizontal zero planes are used as reference planes in these drawings.
G. Paxinos & C. Watson, Rat Brain Stereotactic Coordinates (ed. 7) p. xii/1
Frequency
zero plane typically occurs about 0.01 times per million words in modern written English.
zero plane is in frequency band 3, which contains words occurring between 0.01 and 0.1 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 zero plane, n., 1840–2010
* 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
1840
0.0014
1850
0.0018
1860
0.0017
1870
0.0019
1880
0.0024
1890
0.0027
1900
0.0032
1910
0.0038
1920
0.0046
1930
0.0068
1940
0.0084
1950
0.0095
1960
0.01
1970
0.011
1980
0.011
1990
0.011
2000
0.01
2010
0.009
Originally published as part of the entry for zero, n. & adj.