"Form of Carter"
The name Karder is commonly a male name from the "English" origin.
Karder is a respelling of Carter, with the initial C replaced by K. The substitution matches the pattern seen in Karter, a K-spelling of Carter that also appears in United States birth records. The Karder spelling itself carries no separate meaning or earlier history.
Carter means "Driver of a Cart".
The pronunciation of Karder is KAR-der.