An avatar (avatāra) is an entity who “descends,” generally from some supernatural realm into the world of three dimensions. It is also any new embodiment of an old idea (https://www.merriam webster.com/dictionary/avatar). But in common parlance—and certainly within a Vaishnava context — an avatāra refers to the descent of the Supreme, a manifestation of the divine that comes to us, in this world, out of love and compassion. As a side note, it should be immediately pointed out that, with few exceptions, an avatāra is a completely spiritual form of God become manifest on earth, not in the Christian sense, where the divine becomes fully human and takes on a material body but in a completely otherworldly sense. Therefore, the word “incarnation” might be used to translate avatāra as a matter of convenience, but it is hardly accurate. Incarnation comes from the Latin incarnationem (nominative, incarnatio), which is literally the “act of being made flesh.” The true avatāra, however, specifically descends in his spiritual body, not taking on a fleshy tabernacle at all.