Isthmi, the plural of isthmus, refers to narrow strips of land that connect two larger landmasses. There are a few synonyms for this term, including neck, cape, and promontory. A neck is a narrow strip of land that connects two larger pieces of land, similar to an isthmus. A cape is a point of land jutting out into the sea or other water bodies and can sometimes be used interchangeably with isthmus depending on the context. A promontory, on the other hand, is a high point of land projecting out into a body of water. Regardless of the term used, all refer to a geographical feature that plays a significant role in shaping our planet's landscapes.