pre·​syn·​ap·​tic ˌprē-sə-ˈnap-tik How to pronounce presynaptic (audio)
: of, occurring in, or being a neuron by which a nerve impulse is conveyed to a synapse
a presynaptic membrane
a presynaptic neuron
presynaptically adverb

Example Sentences

Recent Examples on the Web For example, sponge neuroid cells not only express some of the presynaptic machinery of neurons, but also express immune genes. Quanta Magazine, 4 Nov. 2021 The findings from this new study seem to bear on that mystery because the researchers found presynaptic gene sets expressed in neuroid cells and postsynaptic genes expressed in choanocytes. Quanta Magazine, 4 Nov. 2021 It had been observed that vesicles containing neurotransmitters routinely hover in clusters near the presynaptic membrane until they are needed. Quanta Magazine, 26 Nov. 2018

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

Word History

First Known Use

1937, in the meaning defined above

Time Traveler
The first known use of presynaptic was in 1937

Dictionary Entries Near presynaptic

Cite this Entry

“Presynaptic.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2023.

Medical Definition


pre·​syn·​ap·​tic -sə-ˈnap-tik How to pronounce presynaptic (audio)
: relating to, occurring in, or being part of a neuron by which a nerve impulse is conveyed to a synapse
presynaptic terminals
presynaptic inhibition
a presynaptic membrane
presynaptically adverb
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