: a material of a particular kind
: a drug that is considered harmful and whose use is controlled by law or made illegal
: the quality of being meaningful, useful, or important
What made you want to look up substance? Please tell us where you read or heard it (including the quote, if possible).
Take Our 10-Question Quiz
The commonly misspelled words quiz
How strong is your vocabulary?
The Vocab Quiz Game for iPhone & iPad
"Incredibly fun and addictive. And informative!" User Review, iTunes