What is the meaning of Rosario and why did Yuuki name that skill “Mother's Rosario”?

Yuuki's mother turned to Catholicism after learning about her and her family's affliction. This much I'm pretty sure was mentioned in the anime, and it left a strong impression on Yuuki herself.

The author said the skill name is a memento to her mother. (I'll need to find the exact quote later, but it was an answer to a fan's question on Twitter) He used "Rosario" instead of "Rosary" because the Japanese loan word was taken from Portuguese. A rosary itself is a set of prayers called "Hail Mary's". There are also ornaments like necklaces or rings with specific beads for counting the Hail Mary's, also called Rosaries. While it may be speculative, I also think that each hit from the 11-hit skill by Yuuki represents a physical rosary's components, as the typical rosary has ten beads each to represent a Hail Mary, plus a crucifix.