悪念[akunen] evil thought
一念[ichinen] determined purpose
一念ほっき[ichinenhokki] being resolved to (do something)
一般概念[ippangainen] general idea
怨念[onnen] grudge

臆念[okunen] something one always remembers
概念[gainen] general idea
観念[kannen] idea
観念主義[kannenshugi] German idealism
基本概念[kihongainen] basic overview

一次記憶[ichijikioku] first memory
憶説[okusetsu] hypothesis
憶念[okunen] something one always remembers
憶病[okubyou] cowardice
仮想記憶[kasoukioku] virtual memory

憶える[oboeru] to memorize
記憶[kioku] memory
記憶装置[kiokusouchi] storage (device)
記憶媒体[kiokubaitai] storage medium
記憶法[kiokuhou] mnemonic

井の中の蛙大海を知らず[inonakanokawazutaikaiwoshirazu] parochial
雨蛙[amagaeru] tree frog (esp. the Japanese tree frog, Hyla japonica)
蛙の子は蛙[kaerunokohakaeru] like father, like son
蛙跳び[kaerutobi] (game of) leapfrog
殿様蛙[tonosamagaeru] black-spotted pond frog (Rana nigromaculata)

蟇蛙[hikigaeru] toad (esp. the Japanese toad, Bufo japonicus)
蛙又[kaerumata] curved wooden support on top of the main beam of a house, now mainly decorative (shape evocates an open-legged frog)
青蛙[aogaeru] green (tree) frog
赤蛙[akagaeru] any brown or reddish-brown frog (esp. of family Ranidae)

蝦蟇[gama] toad (esp. the Japanese toad, Bufo japonicus)
蟇股[kaerumata] curved wooden support on top of the main beam of a house, now mainly decorative (shape evocates an open-legged frog)
蟇口[gamaguchi] purse with a metal clasp
大蟇[oohikigaeru] cane toad
ヨーロッパ蟇[yooroppahikigaeru] common toad (Bufo bufo)

宮古蟇[miyakohikigaeru] Miyako toad (Bufo gargarizans miyakonis, a subspecies of the Asiatic toad endemic to the Ryukyu Islands)
アジア蟇[ajiahikigaeru] Asiatic toad (Bufo gargarizans)
谷蟇[taniguku] Japanese toad (Bufo japonicus)
蝦蟇鮟鱇[gamaankou] toadfish (any fish of family Batrachoididae, esp. the Pacuma toadfish, Batrachoides surinamensis)
蟇目[hikime] large, perforated, turnip-shaped arrowhead cover made of Japanese bigleaf magnolia or paulownia