For Percy it's always meant a crappy, hand-made card that his mother loves and hangs on the fridge.
Once, when he was ten he brought her some flowers from the park.
But now, Percy knows he needs to get something for his mom.
His decision isn't very hard, he goes to the old candy store she used to work at, and buys everything blue.
"Percy, you shouldn't have," She says.
It means they eat them together.
For Annabeth, it never meant much, when she was younger her step-mom wasn't much of a mother to her, and still isn't.
But this year, she is going to swallow up her pride.
She gives her a card that she bought at the store and signed.
Her step-mother actually smiles at it.
And later, it means going to her room.
"Hey mom," She says. "I would get you a card, except, well, it's sort of hard to get it to you."
It means smiling alone.
For Piper, it never meant anything.
Her and her dad just ignored the holiday, mostly, but it always made her curious about her mom.
This year, she's at camp, and no longer curious.
"Whatever," She says to herself. "Doesn't matter."
It means nothing.
For Jason, it never existed.
It was a mortal holiday, nothing they celebrated at Camp Jupiter.
This year, it means calling Thalia on Iris-message, and talking for as long as he can.
Mostly questions about their mother.
"She wasn't great," He remembers Thalia saying. "But she was ours."
It means visiting a grave.
For Leo, it meant building dumb things for his mom, nothing she would use.
Yet, she always loved his little gifts.
This year, and all the ones since she died it means quiet. Mourning.
It means spending more time on his current project, something to do with armor, he doesn't really remember.
"Leo, you alright?" His sister Nyssa asks.
It means bad dreams that night.
For Hazel, it meant drawing a picture for her mom, who, when she thought Hazel wasn't looking, discarded it.
Later, it meant nothing, no change in the day-to-day schedule.
This year, it means remembering, glad, that her mom didn't go to the fields of punishment.
But it also means tears of grief.
"It's okay," Nico says. "It gets better."
It means she still has family.
For Frank, when he remembered, it meant a last minute anything.
There were years it was a crude card, or drawing, or a picture of them. His mother loved them and told him so.
This year, it means thankfulness, that he got such an amazing mother, who was always protecting him.
It also means sadness, as he remembered his mother, and his grandmother, both dead.
"Hey mom," He says to her grave. "I love you."
It means saying goodbye.
For you, what does it mean?
After all, this is a holiday that we celebrate uniquely, so what does it mean to you?
Happy Mother's Day.