Used to fill a pause when hesitating in speech.

• A mild placeholder showing uncertainty or searching for words.

To say 'er' while hesitating.

• To fill pauses with 'er'.

An instance of the interjection 'er'.

• A hesitation marker in speech.

English initialism for: earned run; endoplasmic reticulum; entity-relationship; emergency room; estrogen receptor; Einstein–Rosen bridge; enhanced radiation.

• Context-dependent technical abbreviation.