Otama おおたま

It means large sphere

Specifically: a large spherical firework from a cannonball.

Additional derived meanings are:

Large diameter cannonballs

Large prototypical objects such as large steel balls from a pinball room, giant hobo eggs, golden son-in-laws (for a woman), rich men, large bounty hunters, high winning lottery numbers, big shots, and so on.

A derivative meaning is actually used more broadly.