Word

活性酸素

かっせいさんそ
reactive oxygen (i.e. free radicals, which can be destructive at high concentrations)
Word

活性化

かっせいか
activation; stimulation; revitalization; invigoration
Word

活人剣

かつじんけん、かつにんけん
life-saving sword (a killing sword may be a sword of life depending on how it is used)
Word

活用語尾

かつようごび
conjugative suffix (i.e. "-iru" and "-eru" for ichidan verbs, "-i" for i-adjectives, etc.)
Word

活動誌

かつどうし
specialty magazine; information digest
Word

活動写真

かつどうしゃしん
moving picture (i.e. a movie; term esp. used during the silent movie period)
Word

活動者

かつどうしゃ
activist
Word

活動成果

かつどうせいか
results (of an activity)
Word

活用語

かつようご
conjugated word
Word

活動的

かつどうてき
active; dynamic; energetic