Israel (יִשְׂרָאֵל) itself is a combined word form from sarah (שָׂרָה - "to persist, exert oneself, persevere") and El (אֵל – shortened from ayil, which means "mighty strength"). So when you put the two together, that's how we get to an English understanding of the word "Israel" as "God the Almighty persists and strives with."