Like Riccardo Radici’s answer says:
It is a variant of βροῦκος = locust (see: Henry George Liddell, Robert Scott, A Greek-English Lexicon, Βροῦκος)
OP has expanded on his inquiry:
Its a word in the Greek Septuagint.
Ive seen it translated in 3 different ways:
Caterpilar,grasshopper,or lightning.
But I have no idea how they came with these translations.I cant find any background info on this word with the resources i have.
I would appriciate any additional information anyone can give me about this word.
OK:
From LSJ, we know that broûkos is ‘locust’ or ‘locust larva’, and that the word turns up in that meaning in Theophrastus:
Locusts [akrides] are dangerous, wingless locusts [atteleboi] even more so, especially those known as broukoi. (Fragment 174)
We know that Hesychius says it is Ionic, and he gives related forms from other dialects in the same meaning.
Frisk’s Etymological Dictionary notes that the Etymologicum Magnum had speculated it is related to the verb brýkō ‘bite, gnash’. You should always be sceptical about Byzantine etymologies, and Frisk remains so. Frisk is also not persuaded by the connection that some scholars have seen with Russian brýkat’ ‘kick with hind legs’, Ukrainian brykáty ‘to jump around deliberately’.
The Septuagint uses the word, in the form broûkhos, 10 times: Lev 11:22, 3 Ki 8:37, 2 Chron 6:28, Ps 104:34, Amos 7:1, Joel 1:4 (bis), 2:25, Nahum 3:15, 3:16. In most of those instances, it occurs next to akrís ‘locust’ or kámpē ‘caterpillar’. Thus Joel 1:4: “What the locust swarm has left the great locusts have eaten; what the great locusts have left the young locusts have eaten; what the young locusts have left other locusts have eaten.” In the Septuagint: “The leftovers of the caterpillar have been eaten by the locust, and the leftovers of the locust have been eaten by the broukhos; and the leftovers of the broukhos have been eaten by the rust [wheat disease].” (Yes, the Hebrew names four different kinds of locust.)
The word remained in use—though anything in the Septuagint was guaranteed bookish survival: a Byzantine chronicle (Schreiner’s Die byzantinischen Kleinchroniken, 45 §4, says that “in the year 6350 [841–842 AD], on the fifth indiction, broûkhos fell on Sicily.”
Byzantine dictionaries gloss broûkhos as caterpillar or locust; LSJ is betting that the Byzantine dictionaries were just guessing from context (the Septuagint mentions them together), and that any caterpillars were in fact larvae.
I’m not seeing anything linking broûkhos to lightning by googling.
EDIT: This appears to be an error in online versions of Strong’s concordance, which conflate βροῦχος with βροντή ‘thunder’.