It emphasizes uniqueness.
Nothing - it looks like some kind of abbreviation instead of an idiom.
"A penny" isn't an idiom - it's just a one-cent American coin.
Eternal isn't an idiom. It's a word. Idioms are phrases that seem to mean one thing but mean something else.
It's an idiom.
This isn't an idiom. Telling a story means to speak and relay a tale - which can be a true one or a false one.
it means to control someone
It means to raise one eyebrow.
It's kind of like "blew his top", which means that he/someone had an outburst of anger.
This is an idiom meaning to narrow your focus down. It can also mean to narrow your aim and focus on one thing to hit. Picture the zero as a target and you get the idea of the idiom.
This is not an idiom. Some people call their loved one by a pet name like "honey" or "darling" or "sweetie."
This is not an idiom. When you see AS ___ AS ___, you are looking at A Simile. This one is comparing something to the red color of a turkey's wattle.
Those are three unrelated words. An idiom is a PHRASE that seems to mean one thing, but actually means another.