うつ伏せ（うつぶせ、utsubuse）
- on one's stomach

The Japanese word うつ伏せ refers to the position of lying face down, also known as prone position. It describes the action or state of resting with one's chest and stomach facing downward, typically with the head turned to the side. This can apply to people or animals. It implies a state of rest, concealment, or, in some contexts, vulnerability.

⚫︎赤ちゃんはうつ伏せで寝ています。 Translation: The baby is sleeping face down. ⚫︎彼は疲れて、机にうつ伏せてしまいました。 Translation: He got tired and ended up lying face down on the desk. ⚫︎その犬はうつ伏せて、日向ぼっこをしています。 Translation: The dog is lying face down, sunbathing.

You use うつ伏せ to describe someone or something in a prone position. It’s a descriptive term used in various situations, such as describing sleeping postures, the position of an animal, or even a person's posture after collapsing. It can be used in both formal and informal contexts. Depending on the context, it might be used to describe someone in distress, resting, or hiding. The verb forms of うつ伏せ like うつ伏せる (to lie face down) and うつ伏せます (polite form of to lie face down) are also very common.

うつ伏せ is primarily written in hiragana. The kanji form, 伏せ, exists, but it is not commonly used. Therefore, it is best to remember it in hiragana. The verb form,うつ伏せる, often adds the okurigana, as with other Japanese verbs.

There aren't many direct synonyms for the action of lying face down in Japanese, but words that convey a similar state or posture include: ⚫︎伏せる (fuseru) - to lie down; to turn face down, similar to うつ伏せ, but can also refer to a less specific position. ⚫︎横になる (yoko ni naru) - to lie down (sideways). This is not the same, but it describes a related action of assuming a resting position.

The direct antonym of うつ伏せ would be the position of lying face up. However, Japanese uses several words to convey this. ⚫︎仰向け (aomuke) - lying face up, supine position ⚫︎上向き (uwamuki) - facing upwards

彼はテスト中に眠くなり、机にうつ伏せてしまいました。》 ・Translation: He got sleepy during the test and ended up lying face down on the desk. ・Explanation: This sentence describes the action of someone falling asleep on a desk.

彼女は、悲しくて、ベッドにうつ伏せて泣いていた。》 ・Translation: She was sad and was crying, lying face down on the bed. ・Explanation: This sentence describes someone lying face down on a bed due to sadness.

The etymology of うつ伏せ is believed to come from the verb 伏せる (fuseru), meaning "to lie down" or "to turn over," and the prefix うつ (utsu), which intensifies the meaning. This combination results in a clear description of the action of lying face down. The うつ element, though, lacks a precise, well-understood etymological origin.