process vs activity

process and activity both are nouns.

Word	Noun	Adjective	Verb	Adverb
process	Yes	No	Yes	No
activity	Yes	No	No	No

As nouns, activity is a hyponym of process; that is, activity is a word with a more specific, narrower meaning than process:

process: a sustained phenomenon or one marked by gradual changes through a series of states
activity: a process existing in or produced by nature (rather than by the intent of human beings)

As nouns, activity is a hypernym of process; that is, activity is a word with a broader meaning than process:

process (noun)	activity (noun)
a sustained phenomenon or one marked by gradual changes through a series of states	any specific behavior
a particular course of action intended to achieve a result	the trait of being active; moving or acting rapidly and energetically
a natural prolongation or projection from a part of an organism either animal or plant	an organic process that takes place in the body
(psychology) the performance of some composite cognitive activity; an operation that affects mental contents	a process existing in or produced by nature (rather than by the intent of human beings)
a mental process that you are not directly aware of	the state of being active
a writ issued by authority of law; usually compels the defendant's attendance in a civil suit; failure to appear results in a default judgment against the defendant	(chemistry) the capacity of a substance to take part in a chemical reaction

process (verb)	activity (verb)
subject to a process or treatment, with the aim of readying for some purpose, improving, or remedying a condition
perform mathematical and logical operations on (data) according to programmed instructions in order to obtain the required information
deliver a warrant or summons to someone
shape, form, or improve a material
institute legal proceedings against; file a suit against
deal with in a routine way
march in a procession