単

1. prefix single; simple
2. noun, abbreviation singles (tennis, badminton, etc.)
3. abbreviation win bet (bet which predicts the winner of a race)

ひとえ also 一重

1. noun, takes の one layer; single layer
2. monopetalous
3. noun, abbreviation, usu. 単 unlined kimono
4. abbreviation single-edged eyelid; eyelid with an epicanthic fold; upper eyelid with no fold