Definition of neuropil in English:
 neuropil
(also neuropile)
noun ˈnjʊərə(ʊ)pɪlˈn(y)o͝orəˌpil
Anatomy Zoology A dense network of interwoven nerve fibres and their branches and synapses, together with glial filaments.
 Example sentencesExamples
-  The above comparison shows that throughout the locust nervous system, primary sensory neuropils are innervated by NOS-expressing interneurons.
 -  Each ocellus comprises a common lens, a few hundred photoreceptor cells in groups of two to seven with a central rhabdom complex, and a synaptic neuropil where the receptors synapse onto large and small ocellar interneurons.
 -  In the crab stomatogastric nervous system, citrulline is present in a pair of projection neurons that send axons to the synaptic neuropil of the STG.
 -  All respective first-order sensory neuropils are innervated by NOS-containing interneurons.
 -  Interestingly, therefore, the nitrergic innervation of the thoracic sensory neuropils follows the separation of tactile and proprioceptive pathways found in early mechanosensory processing.
 
Origin
  
Late 19th century: probably an abbreviation of obsolete neuropilema, from Greek neuron 'nerve' + pilēma 'felt'.