(1) Strength.
(2) Power of Almighty.

(3) Power.  There are four types of Shakti in a man's life -
Shaareerik Bal (physical power),
Mano Bal or Maanasik Bal (mental power),
Aatm Bal (spiritual power) and
Brahm Bal (God's power).

There are some other Shakti also, tmany of them belong to gods ---
Aadi Shakti - Durgaa or Kaalee
Brahm Shakti - Saraswatee Devee
Vishnu Shakti - Lakshmee Jee
Shiv Shakti    - Gauree
Daivee Shakti - Divine Power
Gyaan Shakti  - Knowledge Power
Ichchhaa Shakti - Will Power, 
Indriya Shakti - Power of Senses,
Kriyaa Shakti - Action Power
Mantra Shakti - Mantra Power
Sangh Shakti - Collective Power - power of doing something collecrively
Shabd Shakti - Word Power

Another Classification
Shakti (includes women) are of two types - Bhogyaa (to be enjoyed) and Poojyaa (to be worshipped). The Bhogyaa sits on the left and the Poojyaa sits on the right. If the worshipper yields to desire for the Poojyaa, he commits the sin of incest with his own mother. For the same reason in Indian culture, a wife sits to the left to her husband, and the mother sits to the right to her son. When Gangaa wanted to marry King Prateep, she sat on his right thigh, that is why Prateep said to her - "Since you have sat on my right thigh, I cannot marry you, but I choose you to be my son's wife, so when my son is born, you may come to him and tell him that I have chosen you as my son's wife." Gangaa returned and then came again to Shaantanu and married him.

(4) In Hindu concept, God is formless, hence neither male nor female. Yet in order to conceive God, God is male, or female or both. The latter choice is more popular. His male form has all the attributes except the might which is the attribute of female. In this concept, the male is Shiv and the female is Shakti. The female has been given many names but they all represent power. With the same concept, in the humans, a female has the power if she can recognize it and use it. This power does not mean the physical power, but the power of qualities - endurance, longevity, fairness and love. By love is meant the love of mother which is the purest, most unselfish, and the strongest form of love experienced in any situation. There might be other kinds of love also which can bring great changes in a man's life.

Many people worship God in male and female as pairs, such as Shiv-Paarvatee, Vishnu-Lakshmee, Indra-Shachee, Raadhaa-Krishn, and Seetaa-Raam. But the concept of Shakti, when used exclusively, refers to Paarvatee only. The most popular names of Paarvatee used in this context are

Ambaa (the mother),
Ambikaa (the mother),
Annapoornaa (who nourishes),
Bhairavee (terror to the wicked),
Chaamundaa (killer of demons),
Chandee (the angry),
Devee (the Goddess),
Durgaa (difficult to access),
Gauree (the fair-complexioned one),
Kaalee (death to the wicked),
Kaamaakshee (fulfiller of desires)
Lalitaa
Mahaakaalee (greater death to the wicked),
Mahishmardinee (slayer of Mahish demon)
Paarvatee
Vijayaa (always giver of victory)

Other Shakti
There are 9 Shakti who should be worshipped while worshipping Soorya -
 Deeptaa,  Sookshmaa,  Jayaa,  Bhadraa,  Vibhooti,  Vimalaa,  Amoghaa,  Vidyutaa,  and Sarvatomukhee.
[Agni Puraan, p 35-36]

Saraswatee's Servants are 9 Tattwaatmikaa Shakti --
Lakshmee,  Medhaa,  Kalaa,  Tushti,  Pushti,  Gauree,  Prabhaa,  Mati,  and  Durgaa

According to Mantra Mahaarnav, their names are --
 Prabhaa,  Maayaa,  Jayaa,  Sookshmaa,  Vishuddhaa,  Nandinee,  Suprabhaa,  Vijayaa, and Sarvsiddhidaa
[Agni Puraan, p 99]

According to Mahaanirvaan Tantra, p 251, there are 8 Shakti --
Braahmee, Naaraayanee, Maheshwaree, Chaamundaa, Kumaaree, Aparaajitaa, Vaaraahee, Narasinhee

Shaakt
There are three sects in Hinduism - Vaishnav, Shaiv and Shaakt. Vaishnav people worship Bhagavaan Vishnu and His Avataar (Raam, Krishn etc); Shaiv people worship Bhagavaan Shiv and his sons - Ganesh and Kaarttikeya and his Gan etc; and Shaakt people worship Shakti (power or Devee - Kaalee, Bhavaanee, Saraswatee etc). Although all kinds of people are found everywhere in India, still one may find UP state people mostly Vaishnav; Southern states people Shaiv; and Bengal people mostly Shaakt.

"Tantra literature gave rise to an extreme group called Shaakt with whom Shiv became less important compared to his consort Bhavaanee (Durgaa). The book "Mahaa Nirvaan Tantra" clarifies the true philosophy of this sect. In this work, God is considered as the Mother of the Universe. It deals with three attitudes - "Pashu Bhaav", "Veer Bhaav", and "Divya Bhaav". In the last attitude the devotee is asked to breach all social restrictions. The practical perversion of this edict resulted in encouraging the eating of meat, consumption of liquor and freedom of sex."
[Aangiras, p 359]