whole, entire, all, complete, fulfill
全 centers on the idea of completeness: something that is whole, entire, or all-encompassing. The sense of 'fulfill' naturally extends from making something complete or bringing it to its full state.
all; entire; whole; altogether
everything; all; the whole
all; whole; entire; complete; total; pan-
perfect; complete
all members; all hands; everyone; everybody; whole crew
safety; security
really; truly; entirely; completely; wholly; perfectly
the whole country
(not) at all; (not) in the slightest
whole; entirety
all one's power (strength, energy, efforts); one's utmost
whole (body); full-length (e.g. portrait)
whole surface; entire
(the) whole
healthy; sound; wholesome
total destruction; complete destruction; annihilation; being wiped out
all-America; pan-American; all of America
full length; total length; overall length
total; full amount; sum
all of Japan; the whole of Japan
perfection; flawlessness
preservation; conservation; maintenance; integrity
the whole area; the entire region; all parts (of)
partial; incomplete; imperfect
全 is thought to combine 入 (enter) and 王 (jewel), suggesting a jewel brought inside to be kept whole and complete. The modern form preserves this structure.
The top looks like a roof (入) covering a jewel (王) underneath. Imagine a precious jewel kept safe and complete under a roof: nothing is missing, it is whole and entire.
For ゼン, picture a Zen garden where every stone and raked line is perfectly complete: Zen -> ゼン, and the whole garden is in harmony.