Entertainment descends from Old French entretenir, built on Latin inter, between, plus tenere, to hold. Its earliest English senses were maintenance and provision: to entertain a guest was to keep them fed and housed; to entertain an army was to pay for its upkeep. By the 1600s it already meant holding someone's attention or mind, as in entertaining an idea; the amusement meaning only took over in the 19th century. The same tenere root gives contain, maintain, sustain, and detain.
Assessment: Fully documented. Note the family resemblance: every cousin of this word is about holding something in place, and the attention-grip meaning predates the screens usually accused of inventing it.
Interesting claims
Enter, tame, them
A viral claim breaks the word into enter, tame, and them: entertainment as a tool to enter your mind, tame your will, and hold the masses. Framed as proof that media was designed as control from the word's birth.
Assessment: False etymology, true anxiety. The pieces are wrong: it is inter plus tenere, not enter plus tame. But here is the uncomfortable part: the real meaning, to hold between, is nearly as possessive as the myth. The conspiracy version did not invent the unease; it just attached it to the wrong syllables.
Stories
Bread and circuses
Juvenal's jab at Rome: the people who once granted commands and offices now want only panem et circenses, bread and games. The story of entertainment as the state's cheapest sedative has been retold about every empire since, including our own screen-lit one.
Assessment: Documented as Juvenal's satire, not as policy. The grain dole and the games were real; whether they pacified Rome or merely accompanied its politics is a fight historians still have. As a story about ourselves, it has never stopped working.
Sources and further reading
OED, entertainment, n., 15th c. senses of maintenance and hospitality, from entretenir, to hold among
Worth asking
The word's real root is "to hold between," and its oldest meaning was keeping something or someone maintained. What, exactly, is being held, and who is doing the holding?