1) Forming or having a delta 2) Like a river mouth 3) Like some river areas 4) Like some river mouths 5) Of a Mississippi region 6) Pertaining to or like a delta 7) Triangular 
• (a.) Relating to, or like, a delta.
Del·ta'ic adjective Relating to, or like, a delta. 
deltaic, deltic Relating to, or like, a delta.
pertaining to or like a delta. · forming or having a delta.