It is a prefix used in Spain. It means valley of. It is widely used in Toponymics. Valdebebas and Valdefuentes are two neighborhoods of Madrid.
We can accept this term as a prefix. Valde- appears as a prefix for many toponymics in almost all the villages of my land and all of Castile such as Valdelayegua, Valdáguila, Valdetoros, Valdecucos, Valdelagua and is equivalent to valley.
VALDE 1. old spanich for Valle de or valley of 2. Ortographic error for BALDE, bucketSynonyms of valde are balde
"Valdebenito name means from the valley of Benito. Valdepeñas from the rocks valley."