U+FF61 Halfwidth Ideographic Full Stop

The Wikipedia has the following information about this codepoint:

The full stop (Commonwealth English), period (North American English), or full point . is a punctuation mark used for several purposes, most often to mark the end of a declarative sentence (as distinguished from a question or exclamation).

A full stop is frequently used at the end of word abbreviations—in British usage, primarily truncations like Rev., but not after contractions like Revd; in American English, it is used in both cases. It may be placed after an initial letter used to abbreviate a word. It is often placed after each individual letter in acronyms and initialisms (e.g. "U.S."). However, the use of full stops after letters in an initialism or acronym is declining, and many of these without punctuation have become accepted norms (e.g., "UK" and "NATO").

The mark is also used to indicate omitted characters or, in a series as an ellipsis (... or …), to indicate omitted words.

In the English-speaking world, a punctuation mark identical to the full stop is used as the decimal separator and for other purposes, and may be called a point. In computing, it is called a dot. It is sometimes called a baseline dot to distinguish it from the interpunct (or middle dot).