Eighty-eleven means: Very many; too many to count; quite a lot.. It is a dialectal or regional word and rarely appears in mainstream teen culture; usage usually points to a family, regional, or literary source rather than peer slang. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.