fill in
填 centers on filling an empty space or gap: putting something in to make it full or complete.
填 combines 土 (earth) with 真, which likely contributes the sound and the idea of filling or making solid. The exact historical development is uncertain.
The left side is earth 土, and the right side 真 looks like a container being filled. Picture shoveling earth into a hole until it is completely filled in.
For テン, imagine filling a hole with ten shovelfuls of earth: ten -> テン, and the earth fills the gap.
filling (up); replenishing; filling in (a tooth); loading (a gun with ammunition, a camera with film, etc.); packing; plugging
loading; charging; filling
covering (a loss, deficit, etc.); making up (for); compensating (for); supplementation
filler (for making plastic, rubber, etc.)
fill character
packing; filling material
jūten tofu; (silken) tofu formed directly in its own packaging
hexagonal close packing
loading material (for making paper); filler
Saturn (planet)
making up (a deficit, loss, etc.); covering; compensation; supplementation; replenishment
ci (form of Chinese poetry)
caulking; calking
tessellation
compensation for a loss
close-packed structure
space-filling
cubic close packing; cubic closest packing
cubic close-packed structure
compensation money