Chapter notes: John wanted to name the baby Catherine. Sherlock calls her Watson. Rosie christens the important people in her life accordingly. What's in a name, after all?

Rosamund Mary Watson.

There was a time, much earlier in their friendship when a different, more callous, version of himself might have confronted John outright. That version of himself definitely would have confronted Mary.

Sherlock had been pleased with the original plan to name the baby Catherine. A strong name. Classic. Literary. John would have called her Cate, and even that would have been acceptable.

But Mary had persisted, and John had acquiesced. Sherlock had never been fond of the name, and once Mary revealed her true identity, it seemed too weighty for the innocent little girl.

He called her Watson from the first moment he held her in his arms. It had seemed important that he be able to call her a name that meant something to John. The tiny, vulnerable, human cradled to his chest (with the wide, expressive, searching, intense eyes just like her father's) deserved a name that reflected integrity of character. Loyalty. Strength. Love, even.

Then suddenly Mary was gone. There was so little of Mary's legacy that John would actually be able to pass on to his daughter, but she could always carry with her her mother's name.

Even after all the heartache and trauma they'd endured, Sherlock continued to call Rosie 'Watson.' His belief in the strength of the name never faltered, despite John's own wavering opinion.

And for her own part, Rosie Watson never questioned that she was loved. Cherished. Adored.

When she was old enough and able to put her own names to the faces she loved and trusted most, John was first, and perhaps most obviously, designated 'dadadada.'

Then came the day Rosie was left alone with Sherlock while John was seeing to the shopping. Sherlock had scrunched his nose and made a silly sound. Rosie squealed in delight, patted his cheeks with slightly sticky hands, and laughed as she christened him 'Owme.'

Sherlock's breath caught in his throat, which was understandable considering the fact that his heart had simultaneously tried to leap right out of him. If not for the squirming toddler in his arms, he would have retreated fully into his mind palace to catalogue the moment for all of eternity. He was blinking back tears and hugging Rosie tightly to his chest when John returned.

"Sherlock? You okay?

With a nod, Sherlock sniffed and kissed Rosie's nose.

"Da!" Rosie shrieked joyfully at John, then patted Sherlock's face. "Owme!" Sherlock gasped and buried his face in Rosie's downy curls.

"Sherlock," John chuckled. "What is the matter?"

"Rosie… She just," he took a deep breath. "Did you hear what she said?"

John nodded. "She was saying it the other day. But I don't know what-"

"I've been teaching her names." He tapped her nose playfully. "Watson." Rosie giggled. John rolled his eyes. Sherlock pointed at John. "John."

"Da! Dadadada!" Rosie clapped her hands.

"I'm sorry, John. I tried to teach her."

"Sherlock," John laughed. "I rather like the name she's given me. I think I'll keep it, if it's all the same to you."

"Very well," Sherlock sighed in feigned resignation, though his smile betrayed him. "And I," he laid his hand on his chest, "am Sherlock Holmes."

"Owme!" Rosie parroted. She grabbed his fingers. "Owme owme owme." Sherlock made a noise that was part sob and part laugh.

John dropped the shopping and left it abandoned by the door. "Oh," he breathed and made no effort to restrain his own tears.

"Yeah," Sherlock huffed a breathy laugh.

"My smart girl," John laughed as he scooped Rosie up and kissed her cheeks until she couldn't stop laughing. He sat in his armchair and studied Sherlock's bewildered expression. "Sherlock, you okay?"

"Better than, actually."

John nodded. "Good." He grinned. "You know, Holmes is tricky to get just right. She icould/i call you da too. Or papa. Or any other-"

"Don't be ridiculous, John. I'm not any of those things."

"Well, that's not true. You're with her as much as I am. You clearly love her. Don't you?"

"Of course," Sherlock whispered.

"And she loves you." John shrugged. "There are plenty of families far more unconventional than ours."

"I think…" Sherlock sniffed. "I think, for now, I rather like the name she's given me as well. It means something to her. Something important. Just like calling you da."

"And you calling her Watson?" John's smile was a bit smug and he laughed when Sherlock's eyes went wide. "You aren't the ionly/i observant one in this house, you know."