A division was a large military unit, above the regimental level.
In a holoprogram set in 1944 France, a German Panzer division was holding position eleven kilometers outside of Sainte Claire. Later on, another German division was stationed near the village. (VOY: "The Killing Game")
In 2375, fifteen Klingon divisions landed on Septimus III and eliminated the Cardassian Eleventh Order, taking the planet. (DS9: "Strange Bedfellows")