The word see is used to describe the words perceive or behold. The idea of the action of seeing is just to perceive. The word see is a verb. See also has a noun form in the word sight, and it’s abstract noun form in the word seeing.
The past participle type of the verb see is seen as in “she was seen eating pizza in the restaurant last night.” The verb see is an irregular verb. The term watch is used in the sense of observe or witness, such as “He watched a family of deer in his backyard.” The purpose of watching is to observe. In the similar way, as the word see, the verb watch also has its abstract noun form in the word “watching,” as in the expression ‘bird watching.’