It can have a few different meanings depending on context:
* Origin: The place or thing where something originates. For example, "The source of the river is in the mountains."
* Information: The person, document, or place where information comes from. For example, "She cited a reliable source for her research."
* Inspiration: The thing that inspires or motivates someone. For example, "Nature is his source of inspiration."
The specific meaning of "la source" will depend on the context of the sentence.