How the fuck is there a statute of limitations for rape in New York?

[Thumpalumpacus]

One definition of "murder" is "the unlawful premeditated killing of one human being by another". So if the killing wasn't unlawful (because there was some statue of limitations preventing a conviction), is it still murder, or is it just a "killing".

The statue of limitations does not confer legality upon any act. It confers immunity from prosecution. Those are two entirely different things. Don't equivocate the concepts.

Here's the DoJ's definition of rape:

The penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim.

Not one word in there about SoLs changing the status of the action, and this from the nation's highest law-enforcement authority.

Here's what the same authority has to say on the nature of SoLs:

A statute of limitations is a statutory limitation on the prosecution of an offense if the formal prosecution is not commenced, usually by return of an indictment or filing of an information, within a specified period after the completion of the offense. Statutes of limitations have been said to be a defendant's primary safeguard against the possibility of prejudice from preaccusation delay. See United States v. Lovasco, 431 U.S. 783, 789 (1977).

A statute of limitations establishes an arbitrary cutoff point; no showing of prejudice is required. Thus, a statute of limitations defense is fundamentally distinct from a claim that a pre-indictment delay violated due process, which involves an evaluation of the reason for the delay and any prejudice to the accused. Lovasco, supra. Statutes of limitations should also be distinguished from post-accusation rights to promptness, such as the constitutional right to a speedy trial and rights under the Speedy Trial Act. Compare USAM 9-17.000 (USAM Chapter on the Speedy Trial Act).

Again, not a word about changing the status of the offense from criminal to legal.