This is also known as thelaw of conservation of energy. The first law of thermodynamics is the application of the conservation of energy principle to heat and thermodynamic processes. The first law makes use of the key concepts of internal energy, heat, and system work. It is used extensively in the discussion of heat engines.
Definition of associate. 1 : closely connected (as in function or office) with another : sharing in responsibility or authority associate judges. 2 : having secondary or subordinate status associate membership in a society.
association. n. 1. a group of people having a common purpose or interest; a society or club. 2. the act of associating or the state of being associated. 3. friendship or companionship: their association will not last. 4. a mental connection of ideas, feelings, or sensations: association of revolution with bloodshed. 5. (Psychology) psychol the mental process of linking ideas so that the recurrence of one idea automatically recalls the other. See also free association.