Good morning,all. Here's hoping you are all well. Today is another in quite a series of dark, gloomy, cold, rainy days in Michigan.
My question this morning is as follows, When I tell my kids to Sleep Tight....what does that really mean???
My son said, it probably means Don't sleep loose....but I would prefer a more informed opinion if anyone has one! :)
Thanks to all and blessings!
Marigold

MARIGOLD!!!!! This is some spooky sh@*!t!!

Only an hour ago I walked out of my son's room having asked the same question - and said to him, "My friends on the internet will know - I'll go ask them". His suggestion was, "Maybe it means the blankets are tucked in tight to stop the bed bugs biting?" (for those that don't know - a reference to the 3rd line: Good night, sleep tight, don't let the bed bugs bite. He's 10 BTW).

C'mon all, put Marigold and me out of our misery!!

stales

this one is just a slightly unconventional usage of 'tight':

adv. (The adj. used adverbially.)

1. Soundly, roundly; = tightly 1. Now chiefly in colloq. phr. (good night) sleep tight, a conventional (rhyming) formula used when parting for the night or at bedtime. Also in slang phr. blow me tight: see blow

1933 E. O'Neill Ah, Wilderness! iii. ii. 101 Good night, Son. Sleep tight.

Mu understanding is that tight refers to the rope woven across the bedframe in older times, to support the mattress.
If the rope was loose, you'd sag or fall.
Marigold, I love your name, by the way: it positively
tastes of sunshine!

Jackie, I'm very vague on this but I think that kind of bed was unknown or very uncommon in Europe, but was rather middle-eastern.

Europeans in the middle ages did not use mattresses. Rather than make a permanent mattress by stuffing straw or the like into a cloth, one would bed down on a pile of straw (and hence would have to literally "make the bed" each night.)

Ancient egyptian nobility used the frame and rope contraption, whose advantage was that by placing the legs in pots of water, you prevented crawling insects from reaching the noble sleeper. The rope served as a hammock, supporting the sleeper directly, without any mattress.