In thermodynamics, the word endothermic describes a process or reaction in which the system absorbs energy from it's surroundings in the form of heat. It is a modern coinage from Greek roots. The prefix endo- derives from the Greek word "endon" (ἔνδον) meaning "within," and the latter part of the word comes from the Greek word root "therm" (θερμ-) meaning "hot." The intended sense is that of a reaction that depends on taking in heat if it is to proceed. The opposite of an endothermic process is an exothermic process, one that releases, "gives out" energy in the form of heat. Thus in each term (endothermic & exothermic) the prefix refers to where heat goes as the reaction occurs. The term endothermic was coined by Marcellin Berthelot (25 October 1827 – 18 March 1907).
The concept is frequently applied in physical sciences to, for example, chemical reactions, where thermal energy (heat) is converted to chemical bond energy.
Read more about Endothermic: Implications For Chemical Reactions, Contrast Between Thermodynamic and Biological Terminology, Examples