乾坤 is a classical Chinese term rooted in the I Ching (易经), where 乾 represents heaven and 坤 represents earth. Together they refer to the entire cosmos — the universe, the world, or the grand scheme of things. It is also used in figurative contexts to mean 'the situation' or 'the state of affairs,' often carrying a sense of fate or destiny (e.g., 扭转乾坤 'turn the tide'). The pairing can also symbolize male and female principles (yin and yang). You'll encounter it in literary, philosophical, or dramatic contexts rather than everyday conversation.