副主席 (fù zhǔ xí) literally means 'vice' (副) + 'main' or 'principal' (主) + 'seat' or 'position' (席), together forming the title 'vice chairperson'. It refers to the second-highest official in an organization, committee, or institution whose head is called 主席 (zhǔ xí, 'chairperson'). Unlike English, which often uses gender-neutral 'chair' or 'chairman', 副主席 is strictly formal and institutional — it appears in political bodies (e.g., China’s National People’s Congress), corporate boards, academic associations, and large NGOs.

The term carries strong connotations of hierarchy and authority. It is never used casually or in informal settings; you wouldn’t call a friend ‘vice chairperson’ of your study group. While the character 席 originally meant 'mat' or 'seat', here it metaphorically denotes an official position — much like the English word 'chair'. The prefix 副 always signals a deputy or subordinate role, and is commonly paired with other leadership titles (e.g., 副校长 fù xiào zhǎng, 'vice principal').