This is the 6625th most frequent Swedish word.
mobiltelefonen
"The mobile phone."
In this sentence, 'mobiltelefonen' is the subject and refers to a specific mobile phone, signified by the definite form.
Mobiltelefonen är ny och har många funktioner.
The mobile phone is new and has many features.
Here, 'mobiltelefonen' is the object of the sentence, indicating a particular mobile phone forgotten at home.
Jag glömde mobiltelefonen hemma.
I forgot the mobile phone at home.
In this case, 'mobiltelefonen' is used to inquire about the location of a specific mobile phone, defined by the definite article.