What is the meaning of the word "synchrony"?

Definitions:

  1. A state in which things happen, move, or exist at the same time. copy to clipboard NOUN
    • Natural-gas prices tend to move in synchrony with oil prices. copy to clipboard
  2. Simultaneous action, development, or occurrence. copy to clipboard NOUN
    • The two guards march toward each other with perfect synchrony. copy to clipboard

Synonyms: