felicity, prosperity, large and strong
嘏 centers on great well-being and abundance: felicity, prosperity, and being large and strong. It describes a state of flourishing and robust good fortune.
嘏 combines 古 (old) with 叚, which likely contributes the sound and may relate to greatness or largeness. The exact historical development is uncertain.
The left side 古 suggests something ancient and time-tested, while the right side 叚 looks like a strong, expansive shape. Together they evoke an old, enduring prosperity that is large and strong.
For カ, imagine a prosperous car (カ) that is large, strong, and brings felicity wherever it goes.