Heat:

Heat is a special type of energy transfer which can take place from one material object, place, or region to the other. For illustration, if you place a kettle of water on a hot stove, heat is move from the burner to the water. This is conductive heat, also known as conduction. The figure is as shown below. Whenever an infrared lamp, at times known as heat lamp, shines on your sore shoulder, energy is then transferred to your skin surface from the filament of the lamp; this is radiative heat, also known as radiation. The figure is as shown below. Whenever a blower-type electric heater heats up a room, air passes via the heating elements and is blown by a fan into the room, where the heated air increase and mixes with the rest of the air in the room. This is convective heat, also known as convection. The figure is as shown below.

Figure: Illustrations of energy transfer, in the form of heat, by conduction (a), radiation (b), and convection (c).

Heat is not fairly the same thing as energy, though the units of heat and energy are defined in the same dimensions. Heat is the transfer of energy which occurs when radiation, conduction, and/or convection take place. At times the energy transfer occurs in only one of these three modes, however sometimes it takes place in two or all three.