What does ER stand for?

What does ER mean?

ER	End Reflect Miscellaneous » Unclassified
ER	endocardial resection Medical » British Medicine
ER	endoluminal repair Medical » British Medicine
ER	Endoplasmic Reticulum Medical » Physiology
ER	endoplasmic reticulum Academic & Science
ER	endoscopic resection Medical » British Medicine
ER	endovascular repair Medical » British Medicine
ER	endurance runner Medical » British Medicine
ER	Energy Release Miscellaneous » Unclassified
ER	energy restriction Medical » British Medicine
ER	Engineered For Racing Community » Sports
ER	English Russian Regional » Language Codes (2 Letters)
ER	Enhanced Response Medical » Physiology
ER	Enjoy The Reruns Miscellaneous » Unclassified
ER	Enjoying Rigoletto Miscellaneous » Unclassified
ER	enoyl reductase Medical » British Medicine
ER	Enslaved Race Governmental » US Government
ER	Enter Rectum Miscellaneous » Unclassified
ER	Entity Relationship Computing » General
ER	Entity Relationships Miscellaneous » Unclassified
ER	environmental resistance Medical » British Medicine
ER	enzyme reactor Medical » British Medicine
ER	Epichlorohydrin Rubber (Homopolymer) Miscellaneous » Plastics
ER	epigastric region Medical » British Medicine
ER	epiregulin Medical » British Medicine

er(interj.): (used to express or represent a pause, hesitation, uncertainty, etc.)