| Noun | 1. | X - the cardinal number that is the sum of nine and one; the base of the decimal system | |
| 2. | X - the 24th letter of the Roman alphabetLatin alphabet, Roman alphabet - the alphabet evolved by the ancient Romans which serves for writing most of the languages of western Europe | |
| 3. | X - street names for methylenedioxymethamphetamineMDMA, methylenedioxymethamphetamine - a stimulant drug that is chemically related to mescaline and amphetamine and is used illicitly for its euphoric and hallucinogenic effects; it was formerly used in psychotherapy but in 1985 it was declared illegal in the United States; "MDMA is often used at parties because it enables party-goers to remain active for long periods of time" | |
| Adj. | 1. | x - being one more than ninecardinal - being or denoting a numerical quantity but not order; "cardinal numbers" | |