It is generally used in the context of neutron star and black hole accretion.
To achieve an approximate form of the Bondi accretion rate, accretion is assumed to occur at a rate where: The Bondi radius comes from setting escape velocity equal to the sound speed and solving for radius.
A more complete solution can be found in Bondi's original work and two other papers.
When a planet is forming in a protoplanetary disk, it needs the gas in the disk to fall into its Bondi sphere in order for the planet to be able to accrete an atmosphere.
For a massive enough planet, the initial accreted gas can quickly fill up the Bondi sphere.