Rikaichan is a popup Japanese-to-English/German/French/Russian dictionary add-on for Firefox and Thunderbird.
Denshi Jisho is an easy-to-use and powerful online Japanese dictionary. It lets you find words, kanji and example sentences by searching in many ways.
This is a free online dictionary for learning the kanji of Japanese used in daily life. You can look up the details and pronunciations of the kanji.
Teaches the stroke order of the kanji using animated images and written descriptions. The kanji entries also include common compounds and 四時熟語.
収録語彙数、例文の多さでは、他の追従を許さない。内容に誤りが多いため、他の辞書と併用することが望ましい。
A monolingual Japanese slang dictionary.