ultracoldn.adj.
A. n.
Extreme coldness.
ΘΚΠ
the world > matter > properties of materials > temperature > coldness > [noun] > intense or extreme
frigidityc1420
frigor1599
key-coldness1614
gelidity1656
gelidness1727
ultracold1967
1967 Britannica Bk. of Year (U.S.) 804/3 Ultracold, excessive coldness especially near absolute zero.
1977 A. Hallam Planet Earth 15/1 The Moon's atmosphere..provides little protection from the direct heat of the Sun, and little insulation from the ultracold of space.
B. adj.
Nuclear Physics. Of a neutron: having an energy of the order of 10−7 eV or less.
ΘΚΠ
the world > matter > physics > atomic physics > particle physics > particle participating in strong interaction > baryon > [adjective] > relating to neutron > specific condition
ultracold1969
1969 JETP Lett. IX. 26 Ultracold neutrons are produced and propagate in accordance with the theoretical expectations.
1978 Nature 9 Mar. 127/1 Ultracold neutrons are slow neutrons with velocities of less than 7 m s−1.
1979 Sci. Amer. (U.K. ed.) June 106/1 A striking property of ultracold neutrons is their total reflection from solid surfaces.
This entry has not yet been fully updated (first published 1986; most recently modified version published online June 2019).
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n.adj.1967