This list of isthmuses is an appendix to the article isthmus. The list is sorted by the region of the world in which the isthmus is located. An isthmus ( /ˈɪsθməs/ or /ˈɪsməs/; plural: isthmuses, or occasionally isthmi; from Ancient Greek: ἰσθμός, romanized: isthmos, lit. 'neck') is a narrow piece of land connecting two larger areas across an expanse of water that otherwise separates them.[1] A tombolo is an isthmus that consists of a spit or bar.