Learn Hardcore Portuguese (Portugal): A veterinária vai ligar amanhã para confirmar a consulta. - The veterinarian will call tomorrow to confirm the appointment.

Yes. veterinária is the feminine form of “veterinarian”; the masculine is veterinário. Portuguese often marks professions for gender when the noun allows it:

a veterinária = the (female) vet
o veterinário = the (male) vet Some job titles are epicene (same form for both genders), e.g., o/a dentista.

Why is there a definite article in A veterinária? Would I ever omit it?

Here, A veterinária is a regular noun phrase meaning “the vet,” so the definite article is standard. You omit the article after the verb ser when stating someone’s profession in a general sense:

Ela é veterinária. = She is a vet. But when you use the profession as “the [professional],” you include the article:
A veterinária vai ligar... = The vet will call...

Is vai ligar the future tense? How does it compare to ligará or liga amanhã?

vai ligar (ir + infinitive) = common, neutral “near/planned future” in Portugal; very frequent in speech.
ligará (simple future) = correct but sounds more formal/literary in everyday European Portuguese.
liga amanhã (present with future time) = also common for scheduled or timetabled events. Nuance is subtle; all three can be fine, with vai ligar the most natural in casual contexts.

Does ligar really mean “to call (on the phone)” in Portugal? I thought it was “to turn on.”

Yes, ligar is widely used for phone calls in Portugal: ligar (a/para) alguém = to call someone. It also has other meanings:

ligar a TV = turn on the TV
ligar = connect
Não ligo à política. = I don’t care about politics. For “to call (by phone),” telefonar is also correct and a bit more formal: telefonar a alguém.

Which preposition do I use with ligar when calling someone: a or para?

Both occur in European Portuguese:

To a person: ligar a alguém is very idiomatic: Vou ligar ao João. / Vou ligar à Ana. (note contractions: a + o = ao; a + a = à)
ligar para alguém is also heard, and is common when you conceptualize the destination or when calling a place/number: Vou ligar para a clínica. / Ligar para o 912 345 678. With pronouns, ligar-lhe/ligar-me/ligar-te reflects the underlying a.

How do I say “The vet will call me/you/her/him/us/them tomorrow” naturally?

In European Portuguese, a very common pattern is to attach the pronoun to the infinitive:

A veterinária vai ligar-me amanhã. (me)
A veterinária vai ligar-te amanhã. (you, informal singular)
A veterinária vai ligar-lhe amanhã. (to him/her/you-formal)
A veterinária vai ligar-nos amanhã. (us)
A veterinária vai ligar-vos amanhã. (you plural)
A veterinária vai ligar-lhes amanhã. (to them)

You will also hear the pronoun after the auxiliary: A veterinária vai-me ligar amanhã. Both are common; many teachers prefer the first pattern (on the infinitive) in writing.

Why para confirmar and not a confirmar or por confirmar?

para + infinitive expresses purpose/goal: vai ligar ... para confirmar = “will call in order to confirm.”

a + infinitive is not used for purpose here; in Portugal estar a + infinitive expresses the progressive (e.g., está a ligar = is calling).
por confirmar means “pending/unconfirmed” (e.g., A consulta está por confirmar.).

What exactly does consulta mean here? Could I say a different word for “appointment”?

consulta is the standard word for a medical/health-related appointment (doctor, dentist, vet).
Other options:

marcação = a booking/appointment in general; you can say confirmar a marcação.
For business meetings, use reunião.
So here, confirmar a consulta is the most natural.

Why is it a consulta and not uma consulta or a sua consulta?

a consulta = “the appointment,” implying a specific one already known in context (the one you booked).
uma consulta would introduce a new, nonspecific appointment.
a sua consulta is possible but not necessary; Portuguese often omits the possessive when context makes ownership clear. Also, sua can be ambiguous (his/her/your-formal).

Can I move amanhã around? Where does it sound most natural?

Yes, it’s flexible:

A veterinária vai ligar amanhã para confirmar a consulta. (very natural)
Amanhã, a veterinária vai ligar para confirmar a consulta.
A veterinária vai ligar para confirmar a consulta amanhã. All are fine; initial position adds slight emphasis to “tomorrow.”

How do I pronounce amanhã and what are those marks?

amanhã has the nasal ã (tilde) at the end and nh pronounced like the “ny” in “canyon.”
European Portuguese pronunciation: roughly [ɐ.mɐ.ˈɲɐ̃].
Accents matter: amanhã (tomorrow) vs amanha (a form of the verb “amanhar,” unrelated).

How do I pronounce veterinária and where is the stress?

Stress is on the syllable with the acute accent: na.
European Portuguese: roughly [vɨ.tɨ.ɾi.ˈna.ɾjɐ].
The written accent in veterinária marks the stressed syllable.

Is pra acceptable instead of para in Portugal?

In writing, standard European Portuguese prefers para. In informal speech you’ll hear a reduced form (often pronounced like p’ra/pra), but for careful writing stick with para:

vai ligar amanhã para confirmar... (recommended in writing)

Could I just say A veterinária liga amanhã instead of vai ligar?

Yes. A veterinária liga amanhã is natural in European Portuguese to express a scheduled/expected future action.
Nuance:

liga amanhã = matter-of-fact schedule
vai ligar = plan/near future
ligará = more formal/literary

Why not say Ela vai ligar amanhã? Is the subject pronoun unnecessary?

You can say Ela vai ligar amanhã, but A veterinária specifies who “she” is. Portuguese is a pro-drop language, so subject pronouns are often omitted when the subject is clear from context. Here, naming the profession identifies the caller more precisely than just ela.