When and where to use apostrophes is the most asked question when wording invitations or what's correct on return address labels.
Return Address on your Envelopes:
DO NOT use an apostrophe on your return address!
This the number one mistake made on invitations (See rule 1). On a return address, " The Smiths" means there is more than one person named Smith and the invitation is from them all.
If you put "The Smith's", you are showing plural possession of something (see Rule 2), we don't know what, maybe you mean the house. But if your use "The Smith's" - this would mean the Smith's house is sending the invitations, not the people that make up the Smith family who are the Smiths (plural not possessive - so no apostrophe!)
Grammar Rules of the Apostrophe:
Rule 1.
Do
not use an apostrophe for the plural of a name.
Examples:
We
visited the Sanchezes in Los Angeles.
The Changs have two cats and a dog.
Rule 2.
To show plural possession,
make the noun plural first. Then immediately use the
apostrophe.
Examples:
the
Changs' house
the
Joneses' golf clubs
the
Strauses' daughter
the
Sanchezes' artwork
the
Hastingses' appointment
the
Leeses' books
two boys' hats
two women's hats
two actresses' hats
two
children's hats
Rule 3.
Use the
apostrophe to show
possession. Place the apostrophe before
the s to show singular possession.
Examples:
one boy's
hat
one
woman's hat
one
actress's hat
one
child's hat
Ms.
Chang's house
NOTE: Although names ending in s or an s sound are not required to have the second s added in possessive form, it is preferred.
Mr. Jones's golf clubs
Texas's
weather
Ms.
Straus's daughter
Jose
Sanchez's artwork
Dr.
Hastings's appointment (name is Hastings)
Mrs.
Lees's books (name is Lees)
Rule 4.
Use the
apostrophe where the noun that should follow is implied.
Example:
This was
his father's, not his, jacket.
Rule 5.
Use the
apostrophe with contractions. The apostrophe is always
placed at the spot where the letter(s) has been removed.
Examples:
don't,
isn't
You're
right.
She's a
great teacher.
Rule 6.
With a
singular compound noun, show possession with 's at the end of the word.
Example:
my
mother-in-law's hat
Rule 7.
If the
compound noun is plural, form the plural first and then
use the apostrophe.
Example:
my two
brothers-in-law's hats
Rule 8.
Use the
apostrophe and s after the second name only if
two people possess the same item.
Examples:
Cesar and
Maribel's home is constructed of redwood.
Cesar's
and Maribel's job contracts will be renewed
next year.
Separate ownership.
Cesar and
Maribel's job contracts will be renewed next year.
Joint ownership of more than one contract.
Rule 9.
Never use an
apostrophe with possessive pronouns: his, hers, its,
theirs, ours, yours, whose. They already show
possession so they do not require an apostrophe.
Correct:
don't,
isn't
Incorrect:
You're
right.
Rule 10.
The only time
an apostrophe is used for it's is when it is a
contraction for it is or it has.
Examples:
It's a
nice day.
It's your
right to refuse the invitation.
It's been
great getting to know you.
Rule 11.
The plurals
for capital letters and numbers used as nouns are not
formed with apostrophes.
Examples:
She
consulted with three M.D.s. BUT She went to three M.D.s' offices.
The apostrophe is needed here to show plural possessive.
She
learned her ABCs.
the 1990s not the 1990's
the '90s
or the mid-'70s not the '90's or the
mid-'70's
She
learned her times tables for 6s and 7s.
Exception:
Use
apostrophes with capital letters and numbers when the
meaning would be unclear otherwise.
Examples:
Please
dot your I's.
You
don't mean Is.
Ted couldn't distinguish between her 6's and 0's.
You
don't mean Os.
Rule 12.
Use the
possessive case in front of a gerund (-ing word).
Examples:
Alex's
skating was a joy to behold.
This does
not stop Joan's inspecting of our facilities
next Thursday.
Rule 13.
If the gerund
has a pronoun in front of it, use the possessive form
of that pronoun.
Examples:
I
appreciate your inviting me to dinner.
I
appreciated his working with me to resolve the conflict.