tokamak
Concise Oxford English Dictionary © 2008 Oxford University Press:
tokamak /ˈtəʊkəmak/
▶noun Physics a toroidal apparatus for producing controlled fusion reactions in hot plasma.
– origin 1960s: Russ., from toroidal′naya kamera s magnitnym polem ‘toroidal chamber with magnetic field’.
'tokamak' also found in these Oxford entries:

