A bomb cyclone is basically a storm that can rival the strength of a hurricane. They're called bomb cyclones or "weather bombs" because of the process that creates them (bombogenesis) basically bombogenesis is a storm that undergoes rapid strengthening.
The word bombogenesis comes from two words: bomb and cyclogenesis. All storms are cyclones and genesis means the creation or beginning and in this case bomb means explosive development so all together it means explosive storm strengthening
Bomb cyclones happen more in winter months and can carry hurricane force winds, cause coastal flooding and HEAVY snow. Bomb cyclones happen when a quickly forming storm results in a drop in atmospheric pressure of at least 24 millibars.
Basically its like a hurricane but stronger sometimes. The wind and flooding make it more like a hurricane but the blizzards and snow make it stronger