What does meiosis mean?
Meiosis is the form of cell division that produces reproductive cells in sexually reproducing organisms. It reduces the number of chromosomes in the resulting cells by half, creating cells such as sperm and eggs that contain a single set of chromosomes. The process takes place in two stages, meiosis I and meiosis II, and is usually followed by fertilization, which restores the full chromosome number in the embryo. Meiosis is also a source of genetic variation because chromosomes are shuffled and exchanged during the process. Its name comes from a Greek word meaning “diminution,” reflecting the reduction in chromosome number. In science and education, meiosis is distinguished from mitosis, the more common process of cell division that generally preserves chromosome number.
nounThe specialized type of cell division in sexually reproducing organisms that reduces the chromosome number in daughter cells by half, producing gametes such as sperm and eggs. It occurs in two successive divisions, known as meiosis I and meiosis II.
- The process of cell division in sexually reproducing organisms that reduces the chromosome number by half and produces haploid reproductive cells.
"The cells in the developing testes undergo meiosis to produce sperm cells with half the normal number of chromosomes."
"Meiosis is essential for producing sperm and egg cells in sexually reproducing organisms."
"Researchers studied how errors in meiosis can lead to abnormal chromosome numbers in embryos."
Used for separate instances of the division; the process itself is normally referred to in the uncountable form.
"The study examined how meioses are coordinated during gamete formation."
Meiosis makes the cells that pass on life possible: without its halving of chromosome number, offspring would receive two full chromosome sets from each parent.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does meiosis come from?
The word comes from Greek meiōsis, meaning “a making smaller” or “diminution.” It was adopted into scientific English in the 19th century in the phrase meiosis division, referring to a type of cell division associated with a reduction in chromosome number. The term is related to mitosis, but the two processes differ fundamentally: meiosis reduces chromosome number, while mitosis generally maintains it.
Related word forms
How meiosis is actually used
The term is chiefly used in biology and genetics. It is normally uncountable when referring to the process, while the plural meioses can refer to individual instances of the division.
Easily confused with meiosis
Meiosis halves the chromosome number and produces gametes, whereas mitosis generally preserves the chromosome number and supports growth, repair, and cell replacement.