an origin, cause / a type, class

counter for number of kinds or types

an origin, cause / a type, class / an interest, appeal

a seed / a kind, type, sort, class, or category / (taxonomy) a species

(slang) Alternative form of 大きいお友達

one day

oceanography

Kyūjitai form of 海洋学: oceanography

marine pollution

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