Definition of "ilium" [ilium]

• The uppermost and widest of the three bones constituting either of the lateral halves of the pelvis. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The ilium is short anterposteriorly relative to the length of the pelvis."
• "Hence the ilium is a pleurapophysis, the ischium and pubis are both hæmapophyses."
• "In the first two groups the pubis projects downward and forward as it does in the majority of reptiles, and the ilium is a high rounded plate; while in the others the pelvis is of a wholly different type, strongly suggesting the pelvis of birds."