There are four parts of Vedas; Samhitas, Brahmanas, Aranyakas and Upanishads. Among these Samhita are those parts which are directly revealed to the seers. ie. They are always eternal syllable by syllable.
So, if a name or a deed is spoken in a Samhita part it is always same without even a change in syllable.
As I discuss in my question here YajurVeda 4.5.1 or 5th Anuvaka uses the names:
"Bhava, Rudra, Sarva, Pasupati, Nilagriva, Sitikantha, Kapardin, Vyuptakesha."
ie. As these names are from Samhita portion these are always eternal syllable to syllable.
Also as described in this chapter of Atharvaveda, Nilalohita/Vratya is surrounded by other 7 forms in each direction:
"Bhava from eastern. Sarva from southern. Pasupati from western. Ugra from Northern. Rudra from Nadir. Mahadeva from zenith. Ishana from intermediate regions."
The above names are also from Samhita portion. ie. They are eternal without change in syllable at all time.
But these same names are used by Brahma to name the Ashtamurti incarnation of Lord Shiva as described in this chapter of YajurVeda Satapatha Brahmana. Brahma goes on naming the eight child as:
"You are Rudra. You are Sarva. You are Pasupati. You are Ugra. You are Asani. You are Bhava. You are Mahadeva. You are Ishana."
If we see above names given by Brahma to the AshtaMurti form of Shiva, we find that Brahma is simply recting the 8 names which are always in Samhita. ie. Brahma is not giving a new name. Brahma is just as a medium to provide the Samhita names to AshtaMurti form.
But these 8 forms are always invisible and one can't see them. They are just inside the creation and everything in Universe gets characteristic nature due to presence of them. YajurVeda Satapatha Brahmana in the same chapter clarifies this as:
That boy entered into the forms one after another; for one never sees him as a mere boy, but one sees those forms of his , for he assumed those forms one after another.
So it becomes clear, that chapter of Satapatha Brahmana is not describing manifestation of Lord Shankara who lives in Kailash mountain. Because he is not in formless existence at all time.
But Lord Shankara who is husband of Parvati and Sati is also manifested through Brahma. And this too is described in this chapter of Atharvaveda.
Through Prajapati he was born. He became Mahadeva. He became Ishana. He is NilaLohita.
Shiva Purana also says the same, as I discuss in this answer.
But he is called by only three names Mahadeva, Ishana and Nilalohita among the popular names in that chapter. But we also call him (Sri Parvatipati) using the names Shiva, Bhava, Rudra, Pasupati etc...
As I discuss in my answer here, the name Shiva is also from Samhita or revealed portion of Vedas. It is stated as:
Namaha Shivaya Cha Shivataraya Cha.
Although it seems like name is used as adjective, but it can be called as Specific name as it is part of Namakam (ie. Salutating names of Lord Shiva). Also YajurVeda 3.60 states:
"Shivo Nãmãsi Swadhisthite..."
You are Known by the name Shiva.
Thus from above it becomes clear Shiva is also a revealed name. The name Shiva is also used in other ancient Upanishads like 1.8 of Kaivalya, 2.2, 2.3, 2.4 of AtharvaSikha, 3.11, 4.14, 4.16, 4.18 of Svetasvatara and so on...
But just as we see from above AshtaMurti incarnation. There Eight incarnations get already revealed name from Brahma.
In the similar way Sri ParvatiPati is also Rudravatar of Lord Shiva who is also known by the name Shiva. So it is likely that he also gets the originally revealed name Shiva by some medium like Brahma or Gods or any deities.
So are there any instances in Vedas where Rudra is named or called by the name Shiva or the name Shiva is used due to certain events taking place? (In such a way that the name "Shiva" denotes a specific event.)