Ninja Dictionary (1)

nin·ja
n. pl. ninja or nin·jas (Origin: Japanese. nin, to endure + ja, person (from Middle Chinese)
A member of a feudal Japanese society of mercenary agents, highly trained in martial arts and stealth (ninjutsu), who were hired for diffrent purposes ranging from espionage to sabotage and assassination.

Kunoichi -
Kunoichi is the female counterpart of male Ninja. During the time of the Tong wars, there was a proliferation of secret societies and “sword hunts” against Japanese ninja. Some of the traditional clans splintered, leaving ronin, who were masterless samurai, many of whom had originated with the “Five Families of the Silent Way”.
Many more women than men survived and began searching for a leader or a cause. Surviving women were occasionally offered the honor of wedding the new master of the house.
The daughter of one assassinated lord, shortly after the wedding to her new husband, invited all the friends and relatives of her new spouse to a feast and poisoned them. This left her with a reputation for ruthless efficiency, many friends loyal to her family, and a full-scale drug operation. She became the new head of the clan. Her real name has been lost to time, but she was known as the “Dragon Lady” (Kunoichi) and that is the name given to women of the Black Dragon Fighting Society.

Ninjutsu -
sometimes used interchangeably with the term ninpō , it is the
martial arts practiced by the shinobi (commonly known as the ninja).

18 Ninjutsu Skills (Ninja Jūhakkei) -
According to Bujinkan members the eighteen disciplines were first stated in the scrolls of Togakure-ryū. Subsequently they became definitive for all ninjutsu schools by providing total training of the warrior in various fighting arts and disciplines.
Ninja jūhakkei was often studied along with Bugei Jūhappan (the "18 samurai fighting art skills"). Though some of them are the same, the techniques of each discipline were used with different approaches by both samurai and ninja.
The 18 disciplines are:
1. Seishin-teki kyōyō (spiritual refinement)
2. Taijutsu (unarmed combat, using one's body as the only weapon)
3. Kenjutsu (sword fighting)
4. Bōjutsu (stick and staff fighting)
5. Shurikenjutsu (throwing shuriken)
6. Sōjutsu (spear fighting)
7. Naginatajutsu (naginata fighting)
8. Kusarigamajutsu (kusarigama fighting)
9. Kayakujutsu (pyrotechnics and explosives)
10. Hensōjutsu (disguise and impersonation)
11. Shinobi-iri (stealth and entering methods)
12. Bajutsu (horsemanship)
13. Sui-ren (water training)
14. Bōryaku (tactic)
15. Chōhō (espionage)
16. Intonjutsu (escaping and concealment)
17. Tenmon (meteorology)
18. Chi-mon (geography)

Bujinkan -
The Bujinkan is a international martial arts organization practicing the martial art (and unconventional warfare tactics) commonly referred to as Bujinkan Budō Taijutsu. The Bujinkan is headed by the Sōke (or grandmaster) of the school, Masaaki Hatsumi. Masaaki Hatsumi is the recognized lineage holder of the nine ryūha, transferred to him in the middle of the 20th Century by his teacher Takamatsu Toshitsugu. Specifically the Bujinkan is known for teaching koshijutsu (pressure point, muscle attacks/tears and joint dislocations), koppojutsu (bone breaking), jutaijutsu (throwing, grappling, ground fighting), dakentaijutsu (strikes), happo bikenjutsu (various modern and traditional weapons), and ninpo tactics and strategies (Ninjutsu).
The Bujinkan organization incorporates the teachings of nine ryūha (ryūha ~ old schools):
- Togakure-ryū Ninpō Taijutsu
- Gyokko-ryū Kosshijutsu
- Kuki Shinden Happō Bikenjutsu
- Kotō-ryū Koppōjutsu
- Shinden Fudō-ryū Dakentaijutsu
- Takagi Yōshin-ryū Jūtaijutsu
- Gikan-ryū Koppōjutsu
- Gyokushin-ryū Ninpō
- Kumogakure-ryū Ninpō