1. あるものを成長に最も適した温度に保つこと(maintaining something at the most favorable temperature for its development)
2. 体の温かさによって卵をかえすために卵の上に座ること(sitting on eggs so as to hatch them by the warmth of the body)
3. 病原体がボディーに入る時、初発症状が現れる時の間の感染の開発におけるフェーズ(the phase in the development of an infection between the time a pathogen enters the body and the time the first symptoms appear)