air mass
Meteorological term for a large body of air with uniform temperature and humidity.
A cold air mass moved south, causing temperatures to drop.
So he's finally joined the ranks of the married men, huh?
cold air mass
Arctic air mass
Antarctic air mass
polar air mass
equatorial air mass
Okhotsk air mass
Sense 1 is a Sino-Japanese compound of 気 (air, atmosphere) and 団 (group, mass). Sense 2 is a jocular homophonic substitution for 既男 (きだん, 'already a man'), using the same reading.