er

ER is defined as an abbreviation for emergency room.

(abbreviation)

An example of an ER is the section of a hospital for immediate care.

Er is defined as something you say when you hesitate during a conversation or talk.

(interjection)

An example of er is what is written in a radio transcript when someone pauses.

See er in Webster's New World College Dictionary

interjection

used when hesitating in speaking, as while searching for a word or collecting one's thoughts: a conventionalized representation of the sound

erbium

Origin: ME -er(e) < OE -ere < WGmc *-arj, *-ārj < or akin to, and reinforced by, L -arius, -arium, agentive suffixes (Anglo-Fr -er, -ier), L -ar (OFr -er), L -atur (OFr -ëure), L -atorium (OFr -ëor, Fr -oir), L -ator (OFr -ëor)
1. a person having to do with, esp. as an occupation or profession: added to nouns: hatter, geographer
2. a person native to or living in: added to place names and nouns: New Yorker, cottager
3. a thing or action connected with: added to nouns, noun compounds, and noun phrases
4. a person or thing that ____s: added to verbs: roller
Origin: ME -re, -er < OE -ra
forming the comparative degree of many adjectives and adverbs: later, greater
Origin: ME < Anglo-Fr inf. suffix
the action of ____ing: added to verb bases in legal language: demurrer, repleader
Origin: ME -ren, -rien < OE -rian, freq. suffix
repeatedly: added to verbs and verb bases: flicker, patter

See er in American Heritage Dictionary 4

interjection

Used to express hesitation or uncertainty.

The symbol for the element erbium.

abbreviation

emergency room

suffix

a. One that performs a specified action: swimmer.
b. One that undergoes or is capable of undergoing a specified action: broiler.
c. One that has: ten-pounder.
d. One associated or involved with: banker.
a. Native or resident of: New Yorker.
b. One that is: foreigner.