chemical bond

After 10 years of not even seeing a book on chemistry, I interviewed for my present job. One of the panel members asked me to define a bond in one sentence. This stumped me since I could not think of a one line definition....I thought there are too many kinds of bonds and we cannot define the chemical bond in a single definition. So I answered in a general manner something that I thought did not exclude any of the different kinds of bonds I knew of. The person was not happy. He wanted a single line definition and he then gave me such a definition. I do not remember it, but even after the 10 years hiatus, I thought it was too narrow and excluded ferrocenes, and such molecules.
Now an interesting article .