speculation-n; 3 Senses

Sense Number 1: a belief, a conjecture, a hypothesis

Commentary: SPECULATION[+state][+belief][+conjecture]
NOTE: implies a specific belief or hypothesis that is being advocated.

The speculation that electricity and magnetism are the same force was proved experimentally.
These speculations about genetics and IQ are quite controversial.
It is not a mere speculation that temperatures have risen notably in the last 100 years.
My speculation is that their marriage won't last three years.

WordNet 3.0 Sense Numbers: 1, 2, 4

Sense Number 2: the activity of supposing, surmising, pondering

Commentary: SPECULATION[+activity][+mental][+pondering]
NOTE: focus is on a fluid activity of pondering, it does not imply the adoption of a specific belief or conjecture to be advocated. (see Sense 1)

There is much speculation over whether he will resign.
They sit around making idle speculations about what could happen.
Bob thinks speculations about the meaning of life are pointless.

WordNet 3.0 Sense Numbers: 4

Sense Number 3: making risky financial investments

Commentary: SPECULATION[+activity][+investment][+financial][+risky]

His uncle lost a fortune in land speculations in Florida.
Don't make speculations in junk bonds unless you can afford to lose the money.
Speculation on the gold market has driven the price up significantly.