PLEDGE

Change the Course: Help Save the Colorado River

pledge /plɛdʒ/ n
  1. a formal or solemn promise or agreement, esp to do or refrain from doing something
  2. collateral for the payment of a debt or the performance of an obligation
  3. the condition of being collateral (esp in the phrase in pledge)
  4. a sign, token, or indication: the gift is a pledge of their sincerity
  5. an assurance of support or goodwill, conveyed by drinking to a person, cause, etc; toast: we drank a pledge to their success
  6. a person who binds himself, as by becoming bail or surety for another
  7. sign the pledge, take the pledgeto make a vow to abstain from alcoholic drink
vb
  1. to promise formally or solemnly
  2. (transitive) to bind or secure by or as if by a pledge: they were pledged to secrecy
  3. to give, deposit, or offer (one's word, freedom, property, etc) as a guarantee, as for the repayment of a loan
  4. to drink a toast to (a person, cause, etc)