Douglas Harper's Etymology Dictionary
Wiktionary
contraction (contraction of could not English)
Usage examples of "couldn't".
Ican't fit much in that dinky thing, but I couldn't take the wash up to the big kettle at the house, because of washing the floor and spinning, When you do wash outside, you have to stay there, to tend the fire and stir it, so you can't do much else at the same time.
Even an Englishwoman couldn't get away with the rudeness of not offering food without exciting remark.
Only Robbie, he says no one's takin' a son of his anywhere, and-well, after that, the poor Woman got right flustered and I couldn't make out but one word to the dozen.
Drunkard's Creek couldn't possibly harbor more than two dozen souls, in a scatter of cabins spread along the banks.
I said, and he gave a small grunt of amusement, whether at my surprise or my language, I couldn't tell.
Fergus's lack of a hand limited what he could do physically, though, and he couldn't be dealing with the paperwork or accounts.
For all the conditions that I couldn't really treat, all the illnesses I couldn't cure .
They couldn't, surely, be meaning to bring the priest to trial on the charge of saying Mass.
She couldn't quite decide between John for John Grey, and-and Ian, for her cousin, but of course they're the same name in any case.
The pocket of warmth around her was snug and perfect, but she couldn't luxuriate while he lay exposed to the chilly midnight air like that.
But no matter how wonderful the lovernaking, there remained some odd sense of distance, some barrier that she couldn't penetrate.
I heard them talking quietly together as they came back from the paddock, voices so low-pitched that I couldn't make out the words.
She couldn't wait to peel Jem's sticky, clutching hands off her skin and speed away into the morning, free as one of the homing geese that honked their way south through the mountain passes.
No, she couldn't pretend she hadn't realized there was more than one motive for this private expedition.
Bug might have the flaws of her greatness, but I couldn't help but admit her virtue as a housekeeper.