110 Periods (English)

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Understanding Periods

A period ends a sentence. Every complete sentence begins with a capital letter and ends with either a period, question mark, or exclamation point. When a period ends a sentence, it is neither a question nor an exclamation. It is simply a statement.

Periods and Independent Clauses

A Period separates two complete independent clauses. A period cannot separate an independent clause from a dependent clause. Likewise, a period cannot separate an independent clause from a restrictive or non-restrictive clause, provided the non-restrictive clause is not an independent clause, which should be obvious. To be clear, a period can never separate a dependent clause from an independent clause.

Other Uses of Periods

A period can be used following each letter of an acronym. In such cases, that would be because the word was not clearly an acronym without the periods. For example, scuba was first written as S.C.U.B.A.
A period can be placed at the end of an abbreviation, such as dept. or Mrs.
In dialogue or monologue. A period can be used to signify that each letter of a word be read independently.
A period acts as a decimal point in numbers. Integers are the numbers written without periods. A floating point decimal is the mathematical nomenclature of a number with a decimal point.
A period can be used in a series of three periods to symbolize an ellipsis, which is how omitted words are signified.

Notes on Periods

When an abbreviation ends a sentence, only one period is used. However, when within a sentence, an abbreviation is not followed by a capital letter nor a comma despite that it ends with a period; e.g. this Latin abbreviation is followed by lower-case this.
A period is used in computers to separate the different parts of a web address, email address, or file name.
There is never a case when two periods should be next to each other except in an ellipsis or as leaders, such as in a table of contents.
A period can be used to separate and identify parent-child relationships between two or more words. For example, index.two implies the second unit of an index.