Yes, artifact creatures are considered both creatures and artifacts in the game of Magic: The Gathering.
Yes, artifact creatures count as artifacts in Magic: The Gathering.
Yes, artifact lands count as artifacts in Magic: The Gathering.
Yes, artifact creatures are considered artifacts in the game of Magic: The Gathering.
Creatures and artifact creatures have summoning sickness. Artifacts and creatures with haste do not have summoning sickness
An Artifact Creature is simply a creature who is also an artifact. It is subject to all normal rules regarding both creatures and artifacts, and if a spell can be used against a creature or an artifact, it can be used on that creature.
The plural of artifact is artifacts.
Yes. As long as the spell has the Artifact type, the Etherium Sculpter's ability will reduce it's casting cost by one colorless mana. Artifacts, artifact creatures, even mono and poly artifacts (if your really old school) all have their casting costs reduced.
Some strategies for dealing with white artifact creatures in Magic: The Gathering include using cards that can destroy artifacts, cards that can exile creatures, or cards that can prevent them from attacking or blocking. Additionally, using cards that can tap or disable the artifact creatures can also be effective in neutralizing their threat on the battlefield.
There is a Circle of Protection: Artifacts. But there is no Circle that would protect you from non-artifact colourless creatures, such as the Eldrazi. You'd have to use an effect to give them a colour first.
No, permanents are cards on the battlefield, ie Enchantments, Artifacts, Creatures and Planeswalkers that have resolved to the field, as well as Token creatures, and Lands.
An artifact.
It is 'artifactual' / (artefactual) and it means relating to artifacts.