A more thorough explanation:

De bigamis is a Latin term that means "concerning men twice married." It refers to the statute of 4 Edw. st. 3, which is named after the opening words of the fifth chapter. A bigamus is a person who commits bigamy, which is the act of marrying someone while still being legally married to someone else. In historical context, bigamus also referred to a man who married a widow or remarried. Under ecclesiastical law, a bigamus could be denied benefit of clergy.

Example 1: John married Mary, but he never got a divorce from his first wife. Later, he married Jane without telling her about his first marriage. John is a bigamist.

Example 2: After his first wife died, Henry married a widow named Anne. Henry is a bigamus according to historical usage of the term.

These examples illustrate the definition of bigamus as someone who commits bigamy or marries a widow/remarries. In both cases, the individuals were married to more than one person at the same time, which is illegal and considered a form of fraud. The term bigamus is not commonly used today, but it has historical significance in the context of marriage and the law.