系统 (xìtǒng) is the general word for 'system' (connected parts) and 'systematic' (methodical). As a noun, it contrasts with 体系 (tǐxì), which refers to a structured system of ideas or institutions. As an adjective, it is more common than the idiom 有条不紊 (yǒu tiáo bù wěn), which specifically means 'well-organized and orderly'.