ce·faz·o·lin (s?-f?z??-l?n)n. A broad-spectrum cephalosporin antibiotic, C14H14N8O4S3, that is given intravenously in the form of its sodium salt.[cef(a)- + azol(e) + -in.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.