as
She works as a teacher.
She performs the role of a teacher in her job.
used to indicate the function or role of someone or something
He served as a consultant for the project.
He performed the role of a consultant.
She dressed as a pirate for Halloween.
She wore a costume to look like a pirate.
Commonly used to describe temporary or assigned roles.
used to indicate that something happens during the time when something else is taking place
As I was leaving, it started to rain.
During the time I was leaving, it began to rain.
She called as she walked to the station.
She called while she was walking to the station.
Often interchangeable with 'while' or 'when' in this sense.
used to indicate a comparison
She is as tall as her brother.
She has the same height as her brother.
It's not as easy as it looks.
It is not as simple as it appears.
Pairs with 'as' in comparative structures (e.g., 'as...as').
because; since
As it was raining, we stayed indoors.
Because it was raining, we stayed inside.
As you're tired, you should rest.
Since you're tired, you should take a break.
Formal or neutral in tone; less common in casual speech.
in the way that; in the manner that
Do it as I showed you.
Perform the task in the way I demonstrated.
She sings as beautifully as a professional.
She sings in a manner that is as beautiful as a professional.
Used to describe the manner or quality of an action.
Related Phrases
Pro Tip
Comparative Structures
Use 'as...as' for equal comparisons (e.g., 'She is as smart as her sister'). For unequal comparisons, use 'not as...as' or 'less...than' (e.g., 'He is not as tall as his father').
Gold Rule
Role vs. Comparison
Use 'as' to indicate a role (e.g., 'She works as a doctor') and 'like' for comparisons (e.g., 'She runs like a cheetah').
Word Origin
Old English 'eal swā' (all so), meaning 'just as' or 'in the same way as.' Evolved into Middle English 'as' through phonetic reduction.
Usage Notes
'As' is a versatile word with multiple functions. It can act as a conjunction, preposition, or adverb depending on context. Avoid redundancy in comparative structures (e.g., 'as...as possible' is correct, but 'as...as can be' is informal).