填充 (tiān chōng) is a verb meaning 'to fill in' or 'to fill up', often used when adding material, data, or content to complete or occupy space. The character 填 means 'to fill (in)', as in filling blanks or gaps, while 充 means 'to fill' or 'to serve as', carrying the sense of making something full or sufficient. Together, they emphasize the action of completing something by adding substance — whether physical (like stuffing a pillow), digital (filling form fields), or abstract (padding an argument with extra details).

This word appears frequently in both everyday and technical contexts: students fill in worksheets (填空), designers fill shapes in graphic software, and writers may 'pad' a text to meet length requirements. It implies intentionality and purpose — not just random addition, but deliberate completion or reinforcement. While it can sometimes carry a neutral or slightly negative connotation (e.g., 'padding' with irrelevant content), tone and context determine whether it sounds practical or critical.