The specifics were that he forced his fingers inside her without her consent. Under the specific New York statute relevant to the civil case it is only "rape" if you use your dick. Incidentally the victim said he did do that, but for whatever reason the jury didn't go that far.
But he has been found, on the balance of probabilities, to have forced his hand up a woman against her will.
When she said he had raped her, he sued her for defamation and lost.
The judge in that case said,
"The jury … was instructed that it could find that Mr Trump ‘raped’ Ms Carroll only if it found that he forcibly penetrated Ms Carroll’s vagina with his penis.
It could not find that he ‘raped’ her if it determined that Mr Trump forcibly penetrated Ms Carroll’s private sexual parts with his fingers – which commonly is considered ‘rape’ in other contexts – because the New York penal law definition of rape is limited to penile penetration
As the court explained in its recent decision denying Mr Trump’s motion for a new trial on damages and other relief [in the New York case] … based on all of the evidence at trial and the jury’s verdict as a whole, the jury’s finding that Mr Trump ‘sexually abused’ Ms Carroll implicitly determined that he forcibly penetrated her digitally – in other words, that Mr Trump in fact did ‘rape’ Ms Carroll as that term commonly is used and understood in contexts outside of the New York penal law."