Orrmulum or Ormulum, Middle English collection of homilies on the Gospels, in verse, comprising about 10,000 lines in all. The collection was written c.1200 by Orrm (or Orrmin), an Augustinian canon of Lincolnshire. Because the author had his own system of spelling and because the manuscript is probably in his own handwriting, the Orrmulum is of great importance for the study of Middle English phonology.