a mode or system of rule or government

a dictatorial regime.

a ruling or prevailing system.

a government in power.

the period during which a particular government or ruling system is in power.

Medicine/Medical . regimen ( def. 1 ) .

noun

administration , dynasty , establishment , government , incumbency , management , pecking order * , reign , rule , system , tenurenotes:a regime is the organization that is the governing authority of a political unit; a regiment is an army unit smaller than a division , governance