Kunoichi (くノ一?) is a Japanese term for a female ninja. The characters which make up kunoichi are a mix of hiragana (く, ku?), katakana (ノ, no?), and kanji (一, ichi?); thought to be because they resemble the strokes from the kanji for "woman" (女, onna?).
See Special:Whatlinkshere/Etymology:Kunoichi for a list of articles using this term.