Here's why:

* Accretion is the process where smaller particles (dust, ice, gas) collide and stick together, gradually growing into larger objects. This process is how planets, moons, asteroids, and other celestial bodies form.

Other terms related to solar system formation, but not as encompassing as accretion:

* Nebular hypothesis: This is the overall theory that the solar system formed from a collapsing cloud of gas and dust (a nebula).

* Planetesimal: These are the small, rocky or icy bodies that formed during accretion and eventually coalesced into planets.

* Gravitational collapse: This is the initial stage of the nebular hypothesis where gravity pulls the gas and dust cloud together.

Accretion is the key process that drives the formation of all the objects in the solar system, making it the most accurate term.