Standard Disclaimer: Characters belong to JKR.
My Own: Prologue
'Hermy' is what Harry called her when he wanted something. Ronald preferred 'Mione,' leading Fred and George to call her 'Tiny Mione,' or, when she begged them to leave her to her studies, 'Whiny Mione.' Her grandparents loved their little Mimi, and her parents called her dearest, poppet, or just plain Hermione. Hermione Jean if they were angry.
For a long time he only called her Miss Granger, and then Mrs. Snape when it was appropriate. Occasionally he called out, "Hermione" to get her attention in the presence of friends, but only if he desperately needed her to look his way, otherwise he just waited until she looked to him before saying anything at all.
But when they were alone in the dark of their marriage bed, fulfilling their requirement per the ministry's law, he would softly utter his own nickname for her, the only one she didn't despise. "Mion," he whispered as her passion began to reach its peak, and it always sent her tumbling over the edge.
It was typically Severus to be so possessive as to verbally lay claim to her even as he took her, yet remain so insecure as to hide it in a nickname.
"Mion," his lips uttered.
"My own," his heart professed.