Targumim (or: Targums) are translations of the Hebrew Bible into Aramaic. They were translated and used when Jewish congregations increasingly could not understand the biblical Hebrew anymore. Targum Onqelos (also: Onkelos) is the name of the Aramaic translation of the Torah (the first five books of the Hebrew Bible) probably composed in Israel/Palestine in the 1st or 2nd century CE and later edited in Babylon in the 4th or 5th century, making it reflect Jewish Babylonian Aramaic. It is the most famous Aramaic translation and was widely used throughout the Jewish communities.
In many, but not all, cases the translation of Targum Onqelos avoids anthropomorphisms (attribution of human traits, emotions, or intentions) as they relate in the original Hebrew text to God.
The Hebrew of Numbers 12:8 that is translated in English as “the form of the Lord” or similar is translated in Targum Onqelos as “the likeness of the glory of the Lord.” (Source: Schochet 1966, p. 14)