The hyphen is used to join words together and also to separate syllables of a single word. Hyphenation is the use of hyphens. The punctuation mark should not be confused with dashes (en dash –, figure dash ‒, horizontal dash —, and em dash —), which are longer and have their own different use. The hyphen is also not the same as the minus sign −, which is longer and a little more vertically centered in some typefaces.
The hyphen is a single entity looking at it from an orthographic point of view. In terms of display and character encoding, the entity can be exemplified by any of several characters, as well as glyphs (this include soft hyphens, optional hyphens, hard hyphen and non-breaking hyphens), depending on the context in which it’s used. Although hyphens are not be confused with minus signs, and em dashes, there are some overlaps in terms of usage.
Even though various style guides give detailed usage recommendations, the English language doesn’t have definitive hyphenation rules, and they have a substantial amount of overlap in what they advise. The general use of a hyphen is to break words into parts or join ordinarily separate words into a single word. There is no space between a hyphen and either of the elements it binds except when using a “hanging” or suspended hyphen that stands in for a repeated word. Style traditions or conventions that pertain to hyphens (and dashes) have evolved to make reading complex instructions easier. Most editors accept deviations if they help rather than hinder easy comprehension.
When it comes to English verbs and compound nouns, the use of the hyphen, in general, has been declining. Today, some compounds that have been hyphenated are increasingly getting combined into one word or are left with spaces. In spite of decreased use, the use of hyphen in certain compound-modifier constructions and among some authors with specific prefixes remain the norm (Get help with punctuation).
Below are some rules regarding the use of Hyphen:
Naturally, if two or more words come before a noun they modify and act as a single idea, then it should be hyphenated. This is known as a compound adjective.
“an off-campus restaurant”
“a state-of-the-art facility”
If a compound adjective follows a noun, a hyphen is usually not needed.
Use the hyphen when forming original compound verbs for humor, vivid writing or in special situations.
“The man video-games his way through any problem.”
“The Queen of England throne-sat for six decades.”
Hyphenate new, unusual or original compound nouns. By doing so, it avoids creating confusion.
John decided to change his diet and become a no-meater (without the use of hyphen here, no-meater would confuse the reader)
This is one rule for using hyphen that’s often overlooked. The adverb “very” and adverbs that end with “ly” are not hyphenated. For example:
“The very-elegant watch.”
“The finely-tuned watch.”
Now, the sentences above are incorrect. This rule is strictly applied just to adverbs.
“The friendly-looking cat.”
“A family-owned restaurant.”
The sentences above are correct because the examples that are given above (the ly words) are not adverbs.
Rule 3 & 4
Many times, the hyphen is used to tell the ages of things and people. A common rule is to use a hyphen when writing about months, years and any other period of time unless the period of time (days, weeks, months, years) is written in plural form:
“We have a four-year-old child.”
If the sentence is in the plural form, there will be no need for a hyphen.
“The child is four years old.” (Because years is in plural form)
Also learn about other punctuation marks like periods, commas, colons, semicolons, ellipses, dashes, parentheses, brackets, braces, question marks, quotation marks, exclamation marks, and apostrophes)