Noun
1. a message expressing an opinion based on incomplete evidence
2. a hypothesis that has been formed by speculating or conjecturing (usually with little hard evidence);
"speculations about the outcome of the election""he dismissed it as mere conjecture"3. an investment that is very risky but could yield great profits;
"he knew the stock was a speculation when he bought it"4. continuous and profound contemplation or musing on a subject or series of subjects of a deep or abstruse nature;
"the habit of meditation is the basis for all real knowledge"