the word 'tokamak' is a direct loan from russian, where it originated as an acronym. it is formed from the russian words "тороидальная камера с магнитными катушками" (toroidal'naya kamera s magnitnymi katushkami), meaning "toroidal chamber with magnetic coils." the term was coined in the 1950s by soviet physicists igor tamm and andrei sakharov. as a scientific term, it entered english vocabulary in the latter half of the 20th century to describe this specific magnetic confinement fusion device, retaining its original russian-acronym form without further morphological segmentation.

this is a loanword acronym, not composed of classical morphemes.