Number one; unity
Acen is a modern phonetic spelling of the word 'Ace', which is derived from the Latin 'as' meaning a single unit or the number one. It signifies excellence, being the best, or a sense of unity. While its roots are ancient, this specific spelling is a contemporary American invention.
Less common today
Acen isn't in the latest US Top 1000. It last peaked at #2,444 in 2017.
US births per 5-year period, 1990βpresent (SSA data).