Dejahne appears to be a modern stylized form influenced by Deja, from French deja meaning 'already.'
Dejahne appears to be a modern stylized form influenced by Deja, which comes from the French word deja, meaning "already." That root gives the name a subtle sense of immediacy or prior presence, even as the spelling pushes it into a more decorative register.
The added ending makes Dejahne feel more elaborate and individualized than Deja alone. It has the smoothness of contemporary naming fashions, especially those that favor melodic endings and distinctive spellings. The result is a name that feels modern, graceful, and lightly romantic, with a sound that is more about style than historical inheritance.