Here Brahma means ‘one who constantly meditates on the Supreme Being'. Brahmacharini is highly pious and is a peaceful form or is in meditation. She is also known as Tapashcharini, Aparna and Uma.
This form of Durga is related to the severe penance undertaken by Sati and Parvati in their respective births to attain Lord Shiva as husband.
Some of the most important Vratas observed in different parts of India by women is based on the strict austerities followed by Brahmacharini.