A more thorough explanation:

Definition: Exercitus (pronounced eg-zuh r-si-tuhs) is a Latin word that means "an army" or "an armed force." It was used in history to refer to a group of armed men, which could range in number from 4 to an indefinite amount.

Example: Julius Caesar led an exercitus of over 50,000 soldiers during his conquest of Gaul.

Explanation: In this example, the term "exercitus" is used to refer to the large army that Julius Caesar commanded during his military campaign in Gaul. The number of soldiers in his army was far greater than the smaller groups that the term could also refer to.

Definition: Ex eventu (pronounced eks i-ven-too) is a Latin phrase that means "after the event" or "following the occurrence." It is used in history to describe something that happened or was understood only after the fact.

Example: The true cause of the French Revolution was only understood ex eventu, after it had already occurred.

Explanation: In this example, the phrase "ex eventu" is used to describe how the true cause of the French Revolution was only understood after the event had already taken place. This means that people did not fully understand the reasons behind the revolution until after it had already happened.

Definition: Ex facie (pronounced eks fay-see-ee or -shee or -shuh) is an archaic Latin phrase that means "on the face of it," "evidently," or "apparently." It is used to describe something that is obvious or apparent without further inquiry.

Example: Ex facie, the contract appeared to be valid, but upon closer inspection, it was found to be fraudulent.

Explanation: In this example, the phrase "ex facie" is used to describe how the contract appeared to be valid at first glance, but upon closer inspection, it was found to be fraudulent. This means that the fraud was not immediately obvious and required further investigation to uncover.