well in income tax act we have 5 heads under which we categorise the income recieved by the assessee based on the definition given in the respective heads. salaries, income from house property, profit and gains from business and profession, capital gains and income from other sources. these are the five heads. if an income recieved by the assessee could not be brought under the definition of the first four heads and if the said income is not exempted under any provisions of the act, then it will be taxed under the head income from other sources (hereinafter IFOS). IFOS is a residual head to tax income. Gift recieved amounting to ₹ 1,00,000 cannot be taxed under the first four heads. so it will be taxed under IFOS.