Jump To:

• X chromosome
  X chromosome

  noun

  a sex chromosome of humans and most mammals that determines femaleness when paired with another X chromosome and that occurs singly in males.
• X-chromosome
  X-chromosome

  noun

  the sex chromosome that occurs in pairs in the diploid cells of the females of many animals, including humans, and as one of a pair with the Y-chromosome in those of males Compare Y-chromosome

X chromosome

American  

noun

Genetics.

1. a sex chromosome of humans and most mammals that determines femaleness when paired with another X chromosome and that occurs singly in males.

---

X-chromosome British  

noun

1. the sex chromosome that occurs in pairs in the diploid cells of the females of many animals, including humans, and as one of a pair with the Y-chromosome in those of males Compare Y-chromosome

---

X-chromosome Scientific  

/ ĕks′krō′mə-sōm′ /

1. The sex chromosome that in female mammals is paired with another X-chromosome and in males is paired with a Y-chromosome. Very few genes on the X-chromosome have counterparts on the Y-chromosome, and since males have only one X-chromosome, any gene present on it (even if the gene is recessive in females) is expressed in males. In females, one of the two X-chromosomes in each cell is deactivated.

2. See more at sex chromosome See note at sex

---

Etymology

Origin of X chromosome

First recorded in 1910–15