in reference to a hypothetical cloud of small objects beyond Pluto that become comets, proposed 1949 by Dutch astronomer Jan Hendrick Oort (1900-1992), and named for him by 1968.
oolong
oom-pah
oomph
-oon
oops
Oort cloud
ooze
oozy
op-
*op-
op. cit.
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