Real Dictionary

-er
suffix: You add -er to many short adjectives to form comparatives. For example, the comparative of ' nice' is 'nicer'; the comparative of ' happy' is 'happier'. You also add it to some adverbs that do not end in -ly. For example, the comparative of ' soon' is 'so
suffix: You add -er to nouns to form nouns or adjectives which refer to things with a particular characteristic or feature; for example a ' three-wheeler' is a vehicle with three wheels.
suffix: You add -er to the names of some places to form nouns which refer to a person who comes from that place. For example, someone who comes from London is a 'Londoner'.
suffix: You add -er to verbs to form nouns which refer to a person, animal, or thing that does the action described by the verb; for example a ' reader' is someone who reads and a 'money-saver' is something that saves money.
suffix: You add -er to words to form nouns which refer to a person who is associated or involved with the thing described by the word; for example a ' pensioner' is someone who is entitled to a pension.
suffix: You add -er to words to form nouns which refer to a person with a particular job. For example, someone who works in a mine is a ' miner'.

-er in American English
a person having to do with, esp. as an occupation or profession

-er in American English 1
suffix: a suffix used in forming nouns designating persons from the object of their occupation or labor (hatter; tiler; tinner; moonshiner), or from their place of origin or abode (Icelander; southerner; villager), or designating either persons or things from som

-er in American English 2
suffix: a noun suffix occurring in loanwords from French in the Middle English period, most often names of occupations ( archer; butcher; butler; carpenter; grocer; mariner; officer), but also other nouns ( corner; danger; primer). Some historical instances of th

-er in American English 3
suffix: a termination of nouns denoting action or process

-er in American English 4
suffix: a suffix regularly used in forming the comparative degree of adjectives

-er in American English 5
suffix: a suffix regularly used in forming the comparative degree of adverbs

-er in American English 6
suffix: a formal element appearing in verbs having frequentative meaning

-er in American English 7
suffix: a suffix that creates informal or jocular mutations of more neutral words, which are typically clipped to a single syllable if polysyllabic, before application of the suffix, and which sometimes undergo other phonetic alterations bed-sitter; footer; fresh

-er in British English 1
suffix forming nouns: a person or thing that performs a specified action

-er in British English 2
suffix: forming the comparative degree of adjectives ( deeper, freer, sunnier, etc) and adverbs (faster, slower, etc)

E.R. in American English
abbreviation: East Riding (Yorkshire)

er
Er is used in writing to represent the sound that people make when they hesitate, especially while they decide what to say next.
countable noun: The ER is the part of a hospital where people who have severe injuries or sudden illnesses are taken for emergency treatment. ER is an abbreviation for 'emergency room'.

ER in American English
earned run
used when hesitating in speaking, as while searching for a word or collecting one's thoughts: a conventionalized representation of the sound
abbreviation: efficiency report
interjection: (used to express or represent a pause, hesitation, uncertainty, etc.)
the chemical symbol for: erbium

Er in British English
abbreviation for: (in the US) Emergency Room (in hospitals)
the chemical symbol for: erbium

er in British English 1
exclamation: a sound made when hesitating in speech

er in British English 2
the internet domain name for: Eritrea