primitive streak

noun

Definition of primitive streak

: an elongated band of cells that forms along the axis of a developing fertilized egg early in gastrulation and that is considered a forerunner of the neural tube and nervous system

Examples of primitive streak in a Sentence

Recent Examples on the Web Laws limiting embryo research to either 14 days or formation of a structure called the primitive streak exist in several countries, including the United Kingdom, Sweden, and South Korea. Kelly Servick, Science | AAAS, 26 May 2021 In that transition, the embryo forms a furrow called the primitive streak and folds inward on itself while cells mature into different lineages that will later give rise to all the organs and tissues of the body. Kelly Servick, Science | AAAS, 23 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'primitive streak.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of primitive streak

1833, in the meaning defined above

History and Etymology for primitive streak

translation of German Primitivstreifen

Learn More About primitive streak

Time Traveler for primitive streak

Time Traveler

The first known use of primitive streak was in 1833

See more words from the same year

Dictionary Entries Near primitive streak

primitive segment

primitive streak

primitive water

See More Nearby Entries 

Statistics for primitive streak

Cite this Entry

“Primitive streak.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/primitive%20streak. Accessed 19 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for primitive streak

primitive streak

noun

Medical Definition of primitive streak

: an elongated band of cells that forms along the axis of an embryo early in gastrulation by the movement of lateral cells toward the axis and that develops a groove along its midline through which cells move to the interior of the embryo to form the mesoderm

More from Merriam-Webster on primitive streak

Britannica.com: Encyclopedia article about primitive streak

WORD OF THE DAY

Test Your Vocabulary

Odd Habits and Quirks

  • image1926873504
  • Which of the following best describes an easily irritated person?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!