Son of the gray-haired one
A modern American spelling variation of the English surname Grayson. It traditionally denotes the son of a 'gray' or 'reeve' (a local official), but is now chosen primarily for its trendy sound and aesthetic spelling.
Less common today
Greysin isn't in the latest US Top 1000. It last peaked at #4,344 in 2018.
US births per 5-year period, 1990βpresent (SSA data).