A plate of glass marked out into concentric zones or rings alternately transparent and opaque, used like a lens to bring light to a focus.
1890
A zone plate has therefore the power of a condensing lens.
T. Preston, Theory of Light ix. 178
1937
The intensity of the image produced with a zone plate will be greater if alternate zones are not blocked out but are left transmitting, with a phase difference of one half period introduced between them and adjacent zones.
G. S. Monk, Light xii. 167
1978
When the zone plate is illuminated with an X-ray plane wave, a converging spherical wave will come out.
zone plate typically occurs about 0.07 times per million words in modern written English.
zone plate 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 zone plate, n., 1890–2010
* 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
1890
0.0081
1900
0.0093
1910
0.011
1920
0.012
1930
0.018
1940
0.03
1950
0.043
1960
0.051
1970
0.06
1980
0.067
1990
0.075
2000
0.082
2010
0.08
Originally published as part of the entry for zone, n.
zone, n. was first published in 1921; not fully revised.