lexicostatistics
A subfield of linguistics that uses statistical methods to compare vocabulary across languages, often for historical or comparative purposes.
Lexicostatistics is used to estimate the genetic relationships of languages.
Compound of 語彙 (goi, 'vocabulary') + 統計学 (tōkeigaku, 'statistics'). The exact historical derivation is uncertain, but the term follows the pattern of modern academic compounds.