https://www.urbandictionary.com/define.php?term=Cornteen&defid=14833975

Internet slang for “quarantine”, originating from the many times people misspelled that word on social media during the COVID-19 or coronavirus crisis. Often used in posts expressing boredom or frustration related to self-quarantine or 'social distancing' measures.

Sometimes also (mis)spelled ‘corn teen’, ‘corn and teen’, ‘corn in teen’ or ‘corn of teen’.

“Wow, They Making Us Self Cornteen”
“I may not be making babies during this corn teen but by god I’m thinkin about it”
“I’ve been drunk almost everyday of corn and teen”
“Really regret not getting my eyebrows done before corn of teen”
“What y’all doing for the corn in teen?”