water yam; winged yam; purple yam
Refers to the plant Dioscorea alata, a type of yam. The term is rare and usually written in kana.
See also: ダイジョ
In Okinawa, there are dishes that use water yam.
Kanji form is rare; the word is usually written in kana.
The origin is uncertain; the kanji 田薯 literally means 'field potato' and is likely a direct translation or ateji for the plant.