the term "year-by-year" is a modern english compound construction, formed through the reduplication of the noun "year" connected by the preposition "by". this structure follows a common english pattern for creating adjectival or adverbial phrases that emphasize sequential progression, unit by unit. the word "year" itself has a deep germanic lineage, deriving from the proto-germanic "jērą", which is thought to be from the proto-indo-European root "yēr-", meaning "year, season". the preposition "by", from proto-germanic "bī", conveys proximity, succession, or the means by which something is done. when combined, the literal sense of "passing from one year to the next" creates the modern abstract meaning of something occurring or being assessed in annual, sequential increments.

the term is a hyphenated compound formed from the reduplication of the word "year" and the preposition "by". "year" originates from old english "gēar", of germanic origin, related to dutch "jaar" and german "jahr". "by" originates from old english "bī", of germanic origin, related to dutch "bij" and german "bei".