However, this phrase is often used in a more figurative way. It can refer to:
* The third woman: This could be the third woman in a relationship or the third woman in a particular situation.
* The third wife: This could be the third woman in a man's life who becomes his wife.
* A woman who is third in line: This could refer to a woman's position in a hierarchy or a social order.
Without more context, it's difficult to determine the exact meaning of "femme la trois." The context of the phrase is crucial for understanding its intended meaning.