entomologist

one, 1 / the first in order, foremost / the beginning / the best / a kind of; one of something / (card games) an ace / unity / the bottom string of a shamisen or other Japanese musical instrument

staying up late

Clipping of 一千一夜物語 (Issen'ichiya Monogatari, “One Thousand and One Nights”).

each person

volunteering, service activity, labor of love

active person / political activist

active (given to action rather than contemplation)

(physiology) action potential

extracurricular activities; club activities / school club