BOANERGES bō’ ə nûr’ jez (Βοανηργές, Βοανεργές, Βανηρεγές). A surname interpreted as meaning “sons of thunder” and given by Jesus to James and John, the sons of Zebedee, at the time they were chosen apostles (Mark 3:17). The root meaning of the word is uncertain. Mark tr. it without showing why the term was appropriate. Jerome thought it referred to their fiery eloquence; others have taken it as referring to their fiery dispositions. It may be that they were at one time zealots or revolutionaries. Perhaps the epithet reflects the ancient mythology about the Dioscuri (Heavenly Twins), the Sons of Zeus or Thunder.

International Standard Bible Encyclopedia (1915)

The surname bestowed by Jesus upon James and John, the sons of Zebedee, when they were ordained to the apostleship (Mr 3:17). See James. It has also been regarded as an equivalent of the "Heavenly Twins," the Sons of Zeus or Thunder. According to this interpretation, the name Boanerges would represent the Dioscuri in some form or other of their varied presentation in the cults of the Mediterranean (compare Professor J. Rendel Harris in The Expositor, series vii, III, 146).