cosign

When you cosign a document, you sign it with another person. You and your business partner might cosign a lease for your new office space.

You can use the verb cosign in two slightly different ways. First, if two (or more) people put their signatures on a form or letter, you can say they cosign it. In some cases — particularly when you're applying for a loan — a financial institution will require that you have someone cosign, essentially promising that if you can't repay the loan, he or she will be responsible for it. The word dates from the mid-20th century.

Definitions of cosign
  1. verb
    sign jointly
    synonyms: co-sign
    see moresee less
    type of:
    formalise, formalize, validate
    declare or make legally valid
  2. verb
    sign and endorse (another person's signature), as for a loan
    synonyms: co-sign
    see moresee less
    type of:
    endorse, indorse
    sign as evidence of legal transfer
Word Family
EDITOR’S CHOICE

Test prep from the experts

Boost your test score with programs developed by Vocabulary.com’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.

SAT/PSAT

$29.95
  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week

TOEFL

$29.95
  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week

ACT

$29.95
  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week