Beautiful, graceful, or high-born
Alyannah is a modern American elaboration of Alana or Eliana. It likely draws from the Gaelic 'Alannah', meaning 'child' or 'beauty', or the Hebrew 'Eliana', meaning 'God has answered'. The 'y' and 'h' additions reflect contemporary spelling trends for a more decorative appearance.
Less common today
Alyannah isn't in the latest US Top 1000. It last peaked at #7,675 in 2013.
US births per 5-year period, 1990βpresent (SSA data).