2. Proper noun. Tetrasomy X, a rare chromosomal disorder affecting females, caused by the presence of four X chromosomes instead of two present in the usual human karyotype. ¹
3. Adjective. (context: initialism) X-rated, pornographic ¹
¹ Source: wiktionary.com
Lexicographical Neighbors of XXXX
XVII XVIII XX XXI XXII XXIII XXIV XXIX XXL XXS | XXV XXVI XXVII XXVIII XXX female XXXed XXXing XXXs XXY XXY-syndrome | XXY male XX male XYY XYY male XYZ X Prize |