The word gajan in Bengali comes from the word garjan or roar that sannyasis (hermits} emit during the festivities.Alternatively, the word gajan is considered a combination of parts of two words - ga is from the word gram meaning village and jan is from the word janasadharan meaning folk. In this sense gajan is a festival of village folk.
In Shiva’s gajan Shiva is married to Harakali on this day. The sannyasis form the barjatri (bridegroom’s party). In Dharma’s gajan Dharmathakur is married to Mukti.
Fairs are often associated with the celebration of gajan.