In the U.S., the most common word I hear for women that age is "girl". Unfortunately, there's isn't an age-neutral word like "guy" that you can use for women. Note that "boy" always refers to a child, but "girl" does not. (Even older women sometimes refer to themselves are girls. For instance, if a group of women spend an evening together without any men around, they might call it a "girls' night out".) This is probably because of differing social pressures. Women are taught to value youth and beauty, while men are taught to value power and experience.
The common options are:
- Girl: Very common, especially among 18- to 25-year-olds themselves. Somewhat informal. Usually paired with "guy".
- Woman: More formal. Often used to refer to women in abstract instead of a specific woman. Usually paired with "man". Sometimes used to emphasize maturity.
- Lady: Common in plural form, as in "ladies' night". Can be formal or informal depending on the tone and circumstances. Usually paired with "gentleman". In the singular form, usually refers to an older woman. Sometimes used in the traditional sense of "a woman with class".
Some less common options are:
- Young lady: Don't use this unless you want to sound old or archaic. People under 70 mostly use this phrase when disciplining their children.
- Young woman: If you use it informally, this will also make you sound old, but less old than "young lady". Like "woman", it's often used to refer to women in abstract.
- Lass: If you use this in front of Americans, they will think you sound Scottish. (Or Irish. We're easily confused.)
- Gal: Informal. If you are not a native of the southern or southwestern United States, this will sound a bit silly.
- Miss: Very formal. Normally only used in second-person. ("Excuse me, Miss? You dropped your bag.")
- Chick: Very informal and a bit demeaning.
If you see any others, post them in a comment and I'll add them to the list.
So here's my advice. If you're speaking casually, use "girl". If you're speaking formally or technically, use "woman" (or "young woman" if her age is important). If you're ever in doubt, use "woman". Only use the other options for deliberate wordplay.
I don't think you're showing a gender bias. This is a real problem in English, and even native speakers have trouble with it.
There are as many answers to this as there are situations.
In informal settings, one might only give their first name. So, if I'm at a bar and I start chatting with someone, I would usually only give my first name... or if I'm being introduced to new people by friends, I'll only give my first name.
In formal or business settings, one might give both first and last name. So, if I'm introducing myself to a business partner, I'm more likely to use both first and last names. This is often because you want people to be aware of your full name, so if they need to find you later, they can do so.
When giving your name because it may appear on a list, as when checking in to a hotel, it's common to give your last name, as that is usually what the reservation is filed under. So, as an example:
Receptionist: Welcome to the Hotel. May I have the name on the reservation?
Guest: It's under Bond. James Bond.
This could be the case in many different situations other than simply at hotels.
Since you ask what the significance of last names is... well, there are many groups that only use surnames as means of address... particularly within the military or on sports teams. Often, only the surname of the person is known in those cases, with the possible addition of a first initial if the surname is common.
James Bond is a member of a military organization, and started out in the British Navy, so it makes sense that he would introduce himself emphasizing his last name.
Also note that the original Bond books were written in the 1950s and the movies first came out in the 1960s both of which are eras that are much more formal than modern times, so much of the characterization of James Bond stems from that time.
Best Answer
There are fewer differentiating terms in (at least British) English. Nowadays Christian name is used less because of the religious diversity that prevails. First name or forename is used instead. A person's second name (Hermina in your example) is referred to as a middle name. In British English, the last name (i.e. Smith) is referred to as either the last name or the surname.
Little differentiation is made between a full first name (e.g. Elisa) and a less formal or shortened name that a person might use every day (e.g. Lisette or Jet).
Nickname refers more often to a name completely unrelated to the actual name of the person, e.g. someone tall being called 'Stretch'.
I have never heard 'calling name' being used in British English.