An isthmus is a land bridge bordered on both sides by water that connects two larger bodies of land. A narrow strip of land with sea on either side. (dictionary.com) An Isthmus is a narrow strip of land connecting two larger land areas usually with water on either side. Of note, the Isthmus of Corinth connects the peninsula of Peloponnese with the rest of the Greek peninsula, the Isthmus of Panama connects the continents of North and South America (the Americas), and the Isthmus of Suez in Egypt connects Africa and Asia (or Eurasia).
straight bond. Definition. Bond which will pay back the principal on its maturity date, will pay a specified amount of interest on specific dates, and does not carry a conversion privilege or other special features.
Bond-line structure (bond-line formula, skeletal structure, skeletal formula): A representation of molecular structure in which covalent bonds are represented with one line for each level of bond order. single bond is represented with a single line, a double bond is shown by two parallel lines, and a triple bond by three parallel lines. The position of carbon atoms may be shown with letters, or may be implied (in certain circumstances).