Letters you see to be typed, for example S-K-I-P T-E-A

• Challenge for a web user
• Test to ensure a response is not generated by a computer
• Web test that might have accessibility issues
• Suitable leaders of children's holiday activities go after Conservative - it proves humanity
• Spell check?
• Personal check?
• Reading comprehension test?

Wikipedia Word definitions in Wikipedia
A CAPTCHA (a backronym for " C ompletely Automated P ublic Turing test to tell C omputers and H umans A part") is a type of challenge-response test used in computing to determine whether or not the user is human. The term was founded in 2003 by Luis von ...

Wiktionary Word definitions in Wiktionary
n. 1 A CAPTCHA is a human response test that requires you to enter a series of letters and/or numbers and/or symbols correctly to prove you are a human and not a computer program attempting to spam the site. 2 (context by extension English) Anything that ...