first law of thermodynamics vs conservation of energy

first law of thermodynamics and conservation of energy both are nouns.

Word	Noun	Adjective	Verb	Adverb
first law of thermodynamics	Yes	No	No	No
conservation of energy	Yes	No	No	No

As nouns, first law of thermodynamics and conservation of energy are synonyms defined as:

first law of thermodynamics and conservation of energy: the fundamental principle of physics that the total energy of an isolated system is constant despite internal changes

Other synonyms of first law of thermodynamics include law of conservation of energy.

first law of thermodynamics (noun)	conservation of energy (noun)
the fundamental principle of physics that the total energy of an isolated system is constant despite internal changes	the fundamental principle of physics that the total energy of an isolated system is constant despite internal changes