"势均力敌" is formed by combining two parallel two-character phrases: "势均" meaning "equal in power" and "力敌" meaning "matched in strength". The characters "势" (power), "均" (equal), "力" (strength), and "敌" (match) each contribute directly to these phrases, which when joined create a compound word indicating that both power and strength are balanced, resulting in the meaning of being evenly matched.