syn·​ap·​sis | \ sə-ˈnap-səs \
plural synapses\ sə-​ˈnap-​ˌsēz \

Definition of synapsis

: the association of homologous chromosomes that is characteristic of the first meiotic prophase

Examples of synapsis in a Sentence

Recent Examples on the Web

Recent images of slices of a mouse brain require a supercomputer to assemble them into a 3D model of individual neurons and synapses. Ernie Mastroianni, Discover Magazine, "Meet the Man Who Takes Pictures of Microbes," 18 Oct. 2018 Each neuron should have an average of 7,000 connections, mostly through synapses, empty space that must be crossed by chemicals. Jacqueline Detwiler, Popular Mechanics, "The Heroes of Science Who Are Unlocking the Brain," 3 Oct. 2018 Some synapses get pruned, all making the brain more efficient. Karen Campbell,, "Her quest to understand the teenage brain," 12 July 2018 Counsell, usually not much for milestones, offered a quick synapsis of his team's standing. Todd Rosiak, Milwaukee Journal Sentinel, "Brewers' depth once again pays dividends thanks to Keon Broxton," 29 June 2018 This is the lowest layer of the retina and serves to link the light-sensitive tissue above to the synapses which lead to the brain. The Economist, "The eye's structure holds information about the health of the mind," 28 June 2018 In particular, the drugs appeared to fuel the growth of dendritic spines and axons, the appendages that brain cells of all sorts use to reach out in the darkness and create connections, or synapses, with other brain cells. Melissa Healy,, "Psychedelic drugs change brain cells in ways that could help fight depression, addiction and more," 12 June 2018 And in dialogue, his effervescing synapses and manic facility with language—the tools of his trade as a comedian—are stabilized and counter-balanced. James Parker, The Atlantic, "The Wisdom of Russell Brand," 10 June 2018 These structures control the traffic of ions (such as sodium, potassium and calcium) in and out of the cells and neurotransmitters across the synapses—and thus the excitability of certain brain cells and brain networks. R. Allan Purdy, Scientific American, "Can Anything Stop My Migraine?," 1 May 2017

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

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First Known Use of synapsis

1895, in the meaning defined above

History and Etymology for synapsis

New Latin

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Last Updated

18 Jan 2019

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Time Traveler for synapsis

The first known use of synapsis was in 1895

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More Definitions for synapsis


syn·​ap·​sis | \ sə-ˈnap-səs \
plural synapses\ -​ˌsēz \

Medical Definition of synapsis

: the association of homologous chromosomes with chiasma formation that is characteristic of the first meiotic prophase and is held to be the mechanism for genetic crossing-over

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to settle judicially or to act as judge

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