• 汽車きしゃ — train (steam-powered)
• 汽船きせん — steamboat / steamship
• 汽笛きてき — steam whistle
• 汽缶きかん — steam boiler
• 汽力きりょく — steam power
• 蒸汽じょうき — steam (archaic usage)

The kanji 汽 combines the water radical 氵 and the element 气, expressing the image of rising vapor. It refers to water transformed into steam, which led to its frequent use in early transportation vocabulary such as steam trains (汽車) and steamships (汽船). Because these words remain in use as historical and set phrases, 汽 is a meaningful and memorable kanji for learners interested in classic Japanese terms.