D defs.my
Entry 2 senses Webster, 1913

Seasonal

/sēz'-ən-əl/ · Sea·son·al · IPA /ˈsiːzənəl/
01 a. Of or pertaining to the seasons.
  1. 1.
    Of or pertaining to the seasons.
  2. 2.
    Occurring or being used in a specific season; as, seasonal items for sale.
Phrases & compounds
Seasonal dimorphism — the condition of having two distinct varieties which appear at different seasons, as certain species of butterflies in which the spring brood differs from the summer or autumnal brood.