Hello Jennifer,
I was researching my family tree, and I discovered my mother has a cousin named Adagio (we call him Donny or Dom, so I always thought his name was Dominic). It was his father’s name and his father’s father’s name. I know adagio is a music term for playing slowly, but I wondered if there was any meaning beyond that. 
Hi Stephanie,
Adagio is indeed a direction for playing music at a slow or slower tempo. Literally, in Italian, it means “To lay carefully, lay down, subside.”
I, personally, have never heard it as a given name! There are records of it being an Italian surname, which may have been occupational (bricklayer or something?) or possibly just “that slow guy.”
Hope that helps!  We’ll add it to our database.

Jennifer Moss (she/her) is the founder of BabyNames.com, author of The Baby Names Workbook, and Producer of The Baby Names Podcast. Jennifer is widely regarded as the leading expert on popular baby name trends and the naming process, serving as the authoritative source on the subject for national and international media.

Jennifer entered the tech arena in the 80s as a software developer and database architect, and became a pioneer in the Internet industry. In addition to operating BabyNames.com, Jennifer owns a web development agency in central California.