What does it mean and how do you keep it consistent in your writing?
Let me start with an example:
Daniel rolled his eyes and turned towards the kitchen sink, gripping the smooth steel edge to steady himself. Candice wiped her nose on the back of her sleeve and stifled a sob before pivoting quickly on her heels and leaving the room.
If the chapter containing this line is written from Candice's perspective, you are fine. However, if you have focused on Daniel's perspective, you have an inconsistency.
Perspective revolves around what your character can see, taste, smell, hear, feel, and think in that moment of your story. Keeping that in mind, what can our Daniel see, taste, smell, hear, feel, or think? The information provided is limited, and not all senses will be addressed. But we do know a few things.
Daniel is facing the sink. It's a given that he sees said sink, probably a window or a nice backsplash. He hears Candice sniffling behind him, perhaps even hears her footsteps as she leaves the room. And we know that he feels the smooth coolness of the steel sink beneath his fingers. Daniel rolling his eyes also shows - not tells - us that he's frustrated, possibly annoyed.
What Daniel doesn't see is Candice wiping her nose on her sleeve or pivoting on her heels. He doesn't even see her leave the room, though he probably senses it. His back is to her. As often as I tell my children I have eyes in the back of my head, I do not, and it's feasible to assume the same of most humans.
You can fix this inconsistency in two ways: 1) Changing Daniel's actions, or 2) Paring down the description.
1) Daniel rolled his eyes and turned towards the kitchen sink, gripping the smooth steel edge to steady himself. After taking a deep breath, he faced Candice, watching with silent contempt as she wiped her nose with her sleeve. She stifled a sob, pivoted on her heels, and walked out of the room.
In this fix, we've made it so that Daniel is facing Candice. This way, he can see whatever she does prior to leaving the room.
2) Daniel rolled his eyes and turned towards the kitchen sink, gripping the smooth steel edge to steady himself. He heard Candice stifle a sob as her footsteps receded down the hall.
In this fix, we've pared down the description to only include what Daniel could pick up with his senses. We have not changed that his back is to Candice, only limited the description to what he could hear her doing.
Had the example been written from Candice's perspective, she would have been able to see Daniel roll his eyes, turn around, and put his hands on the sink. No edits would be necessary.
Do not confuse perspective with point of view, or who is telling the story. The two are not technically interchangeable. Your established point of view will determine which pronouns you use. Perspective addresses what the bearer of those pronouns can ascertain. Both, however, can be swapped with a scene break or new chapter.