English to English

noun (n)

• the elastic tension of living muscles, arteries, etc. that facilitate response to stimuli(noun.state)

  Example:
  The doctor tested my tonicity.
  

  Synonym:
  tone, tonus
  Antonym:
  amyotonia, atonia, atonicity, atony
  

  source: wordnet30
• The state of healthy tension or partial contraction of muscle fibers while at rest; tone; tonus.(noun)

  source: webster1913