The muscles of his lean body gained mass.

The following derivation is for a body that is gaining mass (accretion).

In clouds below freezing, when ice crystals gain enough mass they begin to fall.

Gravity yanked her downward, as if either she or Stratos had suddenly gained mass.

As 3-D engines themselves become increasingly expensive to design, a few underlying technologies gain critical mass.

According to this theory, particles gain mass by interacting with the Higgs field that permeates all space.

"It typically takes five years for a code to gain critical mass."

"We are marginalizing a segment of Ptero, so as to improve it, and thus gain mass."

Whatever the reasons, the industry is gaining critical mass.

"We choose models who have already started to gain critical mass, regardless of hair or eye color," said a Hearst spokeswoman in response.