at the same time that another thing happens
As the movie ended, the audience stood up to applaud.
She smiled as she opened the birthday gift.
✦ Old English ‘eallswā’ (all so, likewise) shortened over time to ‘als’ and later ‘as’.
to the same degree or amount (used in comparisons)
He is as tall as his brother.
This puzzle is as easy as that one.
✦ From use of ‘as’ in Old English comparisons expressing equality.
because; for the reason that
As it was raining, we decided to stay indoors.
The flight was delayed as the fog was too thick.
✦ Developed from earlier causal use of Old English ‘alswā’, meaning ‘in the same way, since’.
in the role, function, or form of
She works as a nurse in the city hospital.
The box can be used as a small table.
✦ Sense developed in Middle English from comparison meaning to denote a person’s function.
