The "Latin Kingdom" the "Frankish Levant" an the "Crusader States" are all terms used to describe a group of principalities founded in the wake of the First Crusade (1095-1099) and defended and enlarged by subsequent crusade expeditions. The people who conquered and controlled these new principalities were mainly French-speaking western Europeans (hence "Frankish") who adhered to the Roman Christian religious tradition (hence "Latin").
Geographically, the crusader states comprised an area that included parts of modern day Turkey, Syria, Egypt, and Jordan, and all of modern Israel and Lebanon. Other “Frankish” crusading conquests in the eastern Mediterranean included Cyprus, Greece, and parts of Turkey. Collectively, medieval people referred to these territories as
La terre d’Outremer, “the land across the sea.”
You can find out more about the crusader states by listening to the introductory podcast
here.