维系 (wéi xì) is a formal, written-register verb meaning 'to sustain' or 'to maintain'—especially relationships, connections, traditions, or systems that require ongoing effort to keep intact. The character 维 (wéi) originally meant 'to hold up' or 'to support', while 系 (xì) means 'to bind', 'to connect', or 'to tie'. Together, they evoke the image of actively holding together something fragile or intangible, like trust in a marriage, cultural continuity across generations, or diplomatic ties between nations.

This word is rarely used for physical objects or simple actions—it carries emotional weight and implies intentionality, responsibility, and sometimes difficulty. It appears frequently in news reports, academic writing, literature, and formal speeches, but seldom in casual conversation. Learners should avoid using it for everyday situations (e.g., 'sustaining a friendship' is possible but sounds elevated; 'keeping in touch' would be more natural in speech).