Question

What does gravity mean in space?

Answer 1

It is a Gravitational interaction that does not require a medium.
As such this interaction exists in space as well.

Explanation:

To start with see this question Universal Gravitation

We see that a gravitational force is directly proportional to the product of masses of the two bodies.

`F_G prop M_1.M_2`

It is also inversely proportional to the square of the distance between the two.

`F_G prop 1/r^2`

When one of the two bodies is earth, it is termed as gravity, namely force of gravity, acceleration due to gravity.

It is postulated that gravitational interaction requires no medium.
As such this interaction exists in space as well.

Escape Velocity of earth calculated here.

We observe, if a body/rocket attains a speed of more than `approx11.2km//s`, it will then escape the gravity of the earth and continue with its journey in to the space beyond.

As soon as it nears any other celestial object, and its speed is below the escape velocity of that object, it will then get attracted towards it.