'坐地铁' literally means 'sit on the subway' but functions idiomatically as a verb meaning 'to take the subway' or 'to ride the subway'. The character 坐 (zuò) means 'to sit' and is commonly used as a verb prefix for transportation methods, indicating the act of using that mode — similar to 坐公交 (take the bus) or 坐飞机 (take a plane). 地铁 (dìtiě) means 'subway' or 'metro', composed of 地 (dì, 'earth/ground') and 铁 (tiě, 'iron'), reflecting its underground rail infrastructure.

This phrase is neutral in register and widely used across mainland China, especially in cities with subway systems like Beijing, Shanghai, and Guangzhou. It’s typically used in daily conversation to describe commuting, running errands, or traveling within urban areas. Unlike some verbs, it doesn’t require aspect particles like 了 or 过 unless indicating completion or experience — for example, 我坐地铁去公司 (I take the subway to work) vs. 我昨天坐地铁去了公司 (I took the subway to work yesterday).