entertain (v.) (<--) late 15c., "to keep up, maintain, to keep (someone) in a certain frame of mind," from Middle French entretenir, from Old French entretenir "hold together, stick together, support" (12c.), from entre- "among" (from Latin inter; see inter-) + tenir "to hold" (from Latin tenere; see tenet).
Sense of "have a guest" is late 15c.; that of "gratify, amuse" is 1620s. Meaning "to allow (something) to consideration, take into the mind" (of opinions, notions, etc.) is 1610s. [...]
Per the link above, the prefix inter- never explicitly meant 'together'.
So did among evolve to mean together?
The OED's entry for 'entertain, v.' never uses the 'adverb' together in its etymology.
But then how did *entre- + tenir evolve into all these definitions?
Please expose and explain all (hidden and missing) semantic drifts and links. What is a right way of interpreting the etymology, to understand how the semantic jumps abstracted and severed from the original literal meaning?
Beware that the modern French 'entretenir' means far less (ie: is a hyponym) than its English cognate 'entertain'. Why? Did 'entretenir' simply cease its semantic drifter earlier?