“El” is an ancient Semitic term that derives from a root word meaning “strength, power, and might.” In Hebrew, this term is “Elohim.” Both the term “Elohim” and “El” Have closely become associated with the concept of God. In scripture, the term “El” is a common term used to refer to God, but more context is required to distinguish Him from other false gods around Him. As an example, when God introduces himself to Abram, he says that he is “El Shaddai.” The “Shaddai” is used to denote that He is the “All-Sufficient” God and not any other.
Because the term is so generic, “El” (And sometimes “Elohim” as a plural form) has also used to describe other gods; therefore, the addition of descriptors is necessary to distinguish. Typically, these gods are from around ancient Semitic culture as well.
Often in scripture the term “El” is replaced with “Ēl” to denote that it is a singular important deity. Within various cultures, this deity would vary, but within the Hebrew culture it was used to refer to God.
Today, the “-el” at the end of many religious names, such as that of the angels, is used to show that the indicated individual or individuals are in affiliation with or belonging to “Ēl,” or God. This is seen in names such as: Angel, Michael, Gabriel, Raphael, Daniel, Samuel, Emmanuel, etc.
The “-el” or sometimes more popular “-iel” has taken on the meaning “Of or from God,” an indication to the root of the term.
However, in special terms of angels, it’s also important to return to the root term of “Elohim.” Within early translations, the term “Elohim” was sometimes translated to mean “angels.” The “-el” at the end of their names could be a possible reference to this and serve as less a sign that they belong to God and more a sign of their status as angels. This is still being disputed, though, so the traditional meaning is more likely.