Besides “parliamentary democracy,” what’s another vocabulary term you could use to describe both Japan and India?

Parliamentary system, democratic form of government in which the party (or a coalition of parties) with the greatest representation in the parliament (legislature) forms the government, its leader becoming prime minister or chancellor. Executive functions are exercised by members of the parliament appointed by the prime minister to the cabinet. The parties in the minority serve in opposition to the majority and have the duty to challenge it regularly. Prime ministers may be removed from power whenever they lose the confidence of a majority of the ruling party or of the parliament. The parliamentary system originated in Britain (see Parliament) and was adopted in several of its former colonies.