It acts as a preposition in a sentence, showing the relationship between a noun or pronoun and another word in the sentence.
Here's how it works:
* Preposition: "on account of"
* Object of the preposition: the reason or explanation following the phrase
Example:
"I stayed home on account of the rain."
In this sentence, "on account of" connects the noun "rain" (the reason) to the verb "stayed" (the action).