n.
1) to open, usher in the (a) season
2) to close, usher out the (a) season
3) the dead, low, off, slack; high season
4) (sports) the baseball; basketball; fishing; football; hunting; open season
5) the dry; harvest; holiday; hurricane; mating, rutting; monsoon; planting; rainy; tourist season
6) at a season (at that season of the year)
7) in season; out of season
8) (misc.) it's open season on members of the opposition ('members of the opposition are being subjected to attack')