The meaning of Jehovah-nissi in the Bible
(From International Standard Bible Encyclopedia)

je-ho'-va nis'-i (yahweh nicci, "Yahweh is my banner"): So Moses named the altar which he reared to signalize the defeat of the Amalekites by Israel under Joshua, at Rephidim (Exodus 17:15). Septuagint translates "the Lord my refuge," deriving nicci from nuc, "to flee." Targum Onkelos reads, "Moses built an altar and worshipped on it before Yahweh, who had wrought for him miracles" (niccin). The suggestion is that the people should rally round God as an army gathers round its standard. He it is who leads them to victory.

See more on the meaning of Jehovah-nissi in the Bible:
Jehovah-nissi {Easton's Bible Dictionary}
Jehovah-nissi {Hitchcock's Bible Name}

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