膝（ひざ、hiza）
- knee

The Japanese word 膝 (ひざ/hiza) refers to the knee. It's the joint in the middle of your leg, connecting your thigh and your lower leg. It is a very common and essential word in Japanese, used in many different contexts.

⚫︎膝が痛い。 Translation: My knee hurts. ⚫︎膝をつく。 Translation: To kneel. ⚫︎膝の上。 Translation: On the knee.

You can use 膝 (ひざ) in various situations to talk about the knee itself, actions related to it, or its location. For example, if you are describing an injury, talking about a physical action like kneeling, or describing where something is positioned (e.g., on the knee). It's a very straightforward word, so its usage is quite direct.

⚫︎The word is primarily written using the kanji 膝. ⚫︎The reading is ひざ in hiragana. ⚫︎Katakana is not typically used for this word. ⚫︎The okurigana (送りがな) - the hiragana that follows the kanji - is standard (no variations).

There aren't many direct synonyms for "knee" in Japanese. However, depending on context, you might use phrases to describe the area or action.

There isn't a direct antonym for 膝 (ひざ) as it describes a specific body part. However, you could use words that relate to the opposite state, such as “healthy” or “standing” which could be indirectly opposite of the pain or being on your 膝.

転んで膝をすりむいてしまった。 ・Translation: I fell and scraped my knee. ・Explanation: This sentence describes an injury to the 膝.

子供は母親の膝の上で眠った。 ・Translation: The child fell asleep on their mother's lap. ・Explanation: This sentence describes the location of the child in relation to the mother's 膝.

The etymology of 膝 (ひざ) is not precisely documented, but it is believed to be a native Japanese word, which makes it difficult to trace its origins in a more specific way.