hearse
槫 centers on a hearse, a vehicle for carrying the dead. The single given meaning is specific and concrete.
槫 combines 木 (tree, wood) with 專, which likely contributes the sound. The character is associated with a wooden hearse, but the exact historical development is uncertain.
The left side 木 suggests wood, and the right side 專 looks like a specialized vehicle. Picture a wooden cart specially built to carry a coffin: that is a hearse.
For タン, imagine a tan-colored wooden hearse: tan -> タン, and the wood 木 on the left reinforces the image.