A more thorough explanation:

Superplusagium (s[y]oo-p^ər-pl^ə-say-jee-^əm), n.[Law Latin] Hist. A surplus; a remainder.

Superplusagium is a legal term that refers to a surplus or remainder. It is often used in historical contexts.

One example of superplusagium might be a situation where a person sells a piece of land for $10,000, but the buyer only pays $9,000. The $1,000 difference would be considered the superplusagium.

Another example could be a situation where a company has a budget of $100,000 for a project, but they only end up spending $90,000. The $10,000 difference would be considered the superplusagium.

These examples illustrate how superplusagium refers to a surplus or remainder that is left over after a transaction or project is completed.