Is this dictionary Chinese, Japanese or both?
Definitely a English to Japanese Dictionary. You can think of it as a English to Japanese Dictionary (with 漢字 for kanji)

pivotal method -> 要法 has no meaning at all in chinese. But the japanese words ようほう gives it a much better meaning. 

Other words such as 消除有害事物的成本 has meaning in Chinese, but looks translatable to japanese.