The word 千篇一律 is formed by combining the phrase 千篇 (a thousand pieces) and 一律 (one rule) into a four-character idiom, where 千 and 一 are numerals modifying the nouns 篇 (piece) and 律 (rule) respectively, creating a literal meaning of "a thousand pieces, one rule" that structurally highlights a single standard applied to numerous items.