Siddhidatri = Siddhi + Datri. Siddhi means 'powers' datri is 'giver and holder'. Hence Siddhidatri means the one who has all the powers and can give all kind of powers and boons to the seeker, be it human, god or anyone. Goddess manifested herself in the ninth form of divinity named Siddhidatri.
Goddess Parvati shedded off her white skin and wore the dark one to obtain the ferocious form. She did so to kill the demons shumbha and nishumbha. People in India worship her on the seventh day of navratri festival.
Navratri is the famous religious celebration in Bharat (India). It is the occasion celebrating the feminine aspects of energy, called navdurga. Skandamata is the fifth form of Goddess Durga and hence people in India worship her on the fifth day of navratri festival. Know more about the Navratri day 5, mantra, aarti, storta and more...
Second day of navratri is the day of Goddess Brahmacharini. Brahmacharini is the incarnation of Goddess who did great penance. In sanskrit Brahm is the 'ultimate reality' and Charini is 'to follow, behave'. thus Brahmacharini means the one who follows the path towards the parabrahman, the absolute one. The fruit of her hard austerities is the "Shiva", she got married to him.
As we know navratri is for nine days, so the mantra sadhana is for 9 days. Each one of the nine days is dedicated to a particular Goddess, Thus nine goddesses for nine days. Each day has a new mantra. One should recite the mantra of the day along with the durga mantra. Blog gives the information about are the mantras of the each goddess.