देहली means the threshold of a door दीपक means lamp. The role of a lamp is to spread light. If a lamp is put in any room of the house, it will illuminate that room only. But if a lamp is put on the threshold of a house, it will spread its light on both the sides of the threshold. Thus, with reference to the works more than one, done even being at one place this Nyaya देहलीदीपक has come in use.
Thus, to express succinctly the double objectives achieved at a time by one person or thing. This Nyaya statement is used.