What does an apostrophe in a name mean? Examples: D'Artagnan - The Three Musketeers and F'lar - Dragonflight?

Hint: In languages that use the Latin alphabet and some other alphabets, the apostrophe is a punctuation mark and often a diacritical mark. It serves four purposes in English: The absence of one or more letters is noted.

Complete answer:
It normally indicates that a name is a short form of something longer.
Explanation: In these cases, an apostrophe is normally used to signify that the word has been contracted.
For example, the word "not" is frequently abbreviated in English after some verbs, such as: couldn’t didn’t wouldn’t.

The apostrophe is often used in fiction (most often in the Fantasy genre) to make things look more mysterious and to add odd titles. One such example is "F'lar." Fullarton is his full name, according to the Pern Wiki (and the abbreviation of names is said to be a cultural tradition of the dragon riders).

We have a situation similar to this with the name D'Artagnan, but with a historical twist. D'Artagnan's name comes from a real-life person, Charles de Batz de Castelmore D'Artagnan, who was Captain of the Guard's Musketeers and died at the Siege of Maastricht in 1673. In French, the word "de" means "of," so the name literally means Charles of Batz of Castello.

So, what's the deal with the apostrophe here? Since pronouncing a vowel next to a vowel can be awkward in French, contractions are often used to make it sound easier - thanks to @MeneerNask for catching this. Without the contraction, we'd have De Artagnan, which sounds a little uncomfortable when spoken aloud. As a result, the contraction D'Artagnan is used to make it easier to tell.

Note: When an apostrophe is required to indicate a plural family name's possessive form, the name is treated like any other plural noun ending in "s." Consider the following scenario: The Smiths' cat has disappeared.