I don't agree with edith, btw. But that is what makes horse racing. My source is the OED. I would think that a majority of people might agree with her, and perhaps that makes it right, given the nature of language. But upon reflection, she may agree that facts may be alleged without having anything to do with an accusation. I allege that you were present at the meeting. This does not carry the same meaning as accusing you of being at the meeting, which would not make sense unless being there was some sort of crime.
According to Varó (Diccionario de términos jurídicos: Inglés-Español/Spanish-English), allegation is "any statement of fact in a pleading, affidavit or indictment that the contributing party is prepared to prove." Accusation is "a formal charge made to a court that a person is guilty of an offense."
I think everyone who has given his/her opinion is right. I gave mine thinking in "legal" terms...such as the difference between the "alleged killer" and the "accused killer." Of course, I wasn't very clear on it but anyway...that's another problem
Allegation] Declaración formal o informal, al sentido de que exista algún hecho. He alleges that he is a resident of Hidalgo County, but has not provided any evidence. The allegation that District Attorney Oscar McGinnis hired a hitman to kill his wife produced big stories in the Monitor and the Edinburg Daily Review. Allegations in a legal context implies facts as yet unproven, though in conversation, the term is more generally used to mean "accused."
Accusation. Denuncia contra una persona de haber cometido una ofensa o alguna falta moral. McGinnis accused his bother-in-law of murdering his own sister, alleging that he had threatened on numerous occasions to do so. The brother-in-law accused McGinnis. The prosecutor brought charges against McGinnis but took no action against the brother-in-law. The brother-in-law was accused of the crime by McGinnis, but he was not charged. He was not indicted. Many journalists accused George Bush of being a halfwit.
Eventually, the Hidalgo County Grand Jury indicted (instruyeron los cargos, , emitió el auto acusatorio, lo llamaron a juicio) McGinnis for being an accessory to murder; he was removed from his post, and brought to trial. The prosecution produced three tape recordings, four witnesses and a photograph proving the allegations of the defendant's complicity in the crime.
There are many threads on the subject of indictment.
To Trevinboy's point (& welcome to the forum!), acusación formal renders as formal charges. Formal charges are equivalent to an indictment. It gets more complex than this, but the distinction between accuse and allege is often semantic... US (and other) newspapers routinely use the term alleged, as in the alleged wife-beater because the US (and other) justice system supports the notion that an accused person is "innocent until proven guilty." So, even when charges have been brought, the accused person is referred to as an "alleged" perpetrator. Even the act itself is described as "alleged," such as "the alleged theft..." until such time as a conviction is secured.
MRGSHELTON makes some very good points, especaially regarding the use of "alleged" in the USA because of the presumption of innocence.
There is also a difference in usage.
ACCUSE: You accuse a person of some wrongdoing. This person is aslo called the accused".
ALLEGE/ALLEGATION: You allege that there has been some kind of wrongdoing. Or, you make an allegation of wrongdoing. (eg. the board will investigate all allegations of sexual harassment. You wouldn't say "accusations" of sexual harassment.
Note the difference between these sentences:
"he was accused of stealing the jewels"
"the suspect allegedly stole jewelry"
"the alleged thief is accused of stealing the rare jewels"
In summary, you accuse a PERSON, but you allege some kind of MISCONDUCT or WRONDOING.