aneurysm (n.) Look up aneurysm at Dictionary.com
"dilation of an artery," early 15c., from Medieval Latin aneurisma, from Greek aneurysmos "dilation," from aneurynein "to dilate," from ana "up" (see ana-) + eurynein "widen," from eurys "broad, wide" (see eury-). Related: Aneurysmal; aneurysmic.