placenta, sac, sheath
胞 centers on a biological enclosing structure: a placenta, a sac, or a sheath that wraps around and protects something inside.
胞 combines the flesh radical ⺼ with 包, which likely contributes both sound and the idea of wrapping or enclosing, reflecting the biological sac or sheath meaning.
The flesh radical ⺼ on the left suggests something organic, and 包 on the right looks like a wrapping enclosure. Together they form a biological sac or sheath, like a placenta protecting a fetus.
For ホウ, imagine a protective sac that lets out a soft 'hoo' sound when gently pressed: hoo -> ホウ, and the flesh radical ⺼ reminds you it's a living sheath.
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cell
brethren; brothers; fellow countrymen; fellowman; compatriot
spore
single cell
cyst
(ovarian) follicle
spore
B cell; B lymphocyte
embryonic stem cell
natural killer T-cell; NKT cell
natural killer cell; NK cell
STAP cell (proposed but disproven type of pluripotency cell); stimulus-triggered acquisition of pluripotency cell
T cell; T lymphocyte
induced pluripotent stem cell; iPS cell
cancer cell
ameloblast; tooth enamel depositing cell
killer T-cell
killer cell
Graafian follicle
Graafian follicle