The word 天寒地冻 is formed by combining two two-character phrases: 天寒, meaning "the sky is cold", and 地冻, meaning "the ground is frozen". The characters are arranged in a parallel structure where 天 (sky) corresponds to 地 (ground) and 寒 (cold) corresponds to 冻 (frozen), resulting in a compound that literally describes cold air and frozen earth to convey extreme cold.