squirrel
General term for any squirrel (family Sciuridae).
A squirrel is eating nuts in the park.
Japanese squirrel
Specifically the Japanese squirrel (Sciurus lis), a species native to Japan. Often distinguished as ニホンリス in scientific contexts.
See also: ニホンリス
Squirrels gather nuts in preparation for winter.
The Japanese squirrel inhabits Honshu and Shikoku.
The squirrel quickly climbed up the tree.
リス is a tree squirrel that runs and jumps, whereas ムササビ is the Japanese giant flying squirrel that glides using a skin membrane.
栗鼠 (also written リス) means 'squirrel' and is completely unrelated to the rare specialist word リス meaning 'fracture' or 'lithograph', despite sharing the same reading and often the same katakana spelling.
counter for small animals · counter for rolls of cloth · archaic counter for horses · roll of cloth
Katakana is the most common spelling for this animal name.
Hiragana spelling is also used, especially in children's materials.
Kanji spelling is rare and literary; the word is usually written in kana.
The reading developed from the Tang-style Sino-Japanese reading りっす of 栗鼠, the Chinese compound for “squirrel.” The modern spelling リス reflects the later reduced pronunciation.