Help me map ‘syn' + ‘ek' + ‘deskhesthai' to synecdoche?

Synecdoche means “figure of speech in which a part is taken for the whole or vice versa [⋮] from Greek synekdokhe “the putting of a whole for a part; an understanding one with another,” literally “a receiving together or jointly,” from synekdekhesthai "supply a thought or word; take with something else, join in receiving”".

But why’s Syn- relevant to synecdoche? Because taken together, the parts represent the whole?

How does synecdoche involve outness, or outwardness?

What do synecdoches receive? From where or whom or what, do synecdoches receive?Synecdoche means “figure of speech in which a part is taken for the whole or vice versa [⋮] from Greek synekdokhe “the putting of a whole for a part; an understanding one with another,” literally “a receiving together or jointly,” from synekdekhesthai "supply a thought or word; take with something else, join in receiving”".

But why’s Syn- relevant to synecdoche? Because taken together, the parts represent the whole?

How does synecdoche involve outness, or outwardness?

What do synecdoches receive? From where or whom or what, do synecdoches receive?

…or accepting from without?

Part being within a whole as part of it.

Unless it isn’t, and is merely subsumed.

in which case maybe “without accepting” is accurate

As in “in but not of”.

This was fractalicious on Wikipedia:

Kenneth Burke (1945), an American literary theorist, declared that in rhetoric, the four master tropes, or figures of speech, are metaphor, metonymy, synecdoche, and irony. Burke’s primary concern with these four master tropes is more than simply their figurative usage, but includes their role in the discovery and description of the truth. He described synecdoche as “part of the whole, whole for the part, container for the contained, sign for the thing signified, material for the thing made… cause for the effect, effect for the cause, genus for the species, species for the genus”. In addition, Burke suggests synecdoche patterns can include reversible pairs such as disease-cure. Burke proclaimed the noblest synecdoche is found in the description of “microcosm and macrocosm” since microcosm is related to macrocosm as part to the whole, and either the whole can represent the part or the part can represent the whole". Burke compares synecdoche with the concept of “representation”, especially in the political sense in which elected representatives stand in pars pro toto for their electorate.