In the English language, the word “at” has only a single function. This common word is used as a preposition.
This word can be classified as a preposition because it can be used to indicate position in time or place. For instance, in the sample sentence below:
My kids go to bed at nine o’clock.
The word “at” is considered as a preposition because it is used to specify the time “nine o’clock.”
a. expressing location or arrival in a particular place or position
- They live at Winterfell.
b. expressing the time when an event takes place
- The desert is cooler at night.
c. denoting a particular point or segment on a scale
- The prices start at $100.