Kotobank : search from 99 dictionaries and encyclopedia at once.
Edited by Charles Muller, the dictionary provides English definitions for Buddhist terms in a range of languages, including Chinese, Japanese, Korean, Pali, Sanskrit, and Tibetan, as well as pronunciations. It includes A Dictionary of Chinese Buddhist Terms : with Sanskrit and English equivalents and a Sanskrit-Pali index, compiled by William Edward Soothill and Lewis Hodous.
JAANUS: Online dictionary of Japanese Architecture and Art Historical Teminology Compiled by Dr. Mary Neighbour Parent
denki-etcetra Biographical data for 173 late-Edo intellectuals, created by Anna Beerns.
Some 20 reference books below are searchable at once, or individually.
Encyclopedia of Japan is a handy and reliable tool in English.
日本大百科全書（ニッポニカ) this encyclopedia search provides relevant web links as well.