It is never correct to end a letter greeting with a semicolon. Instead, use a comma after the greeting and a period after name: Hello, Mr. Reader.
Semicolons often evoke semi confusion, let’s take a look at the below greeting:
HELLO Ms. Gaertner-Johnston;
What do you think? Is a semicolon correct after the greeting? How about a comma or a colon?
The semicolon is dead wrong. It is NEVER correct after a greeting. Never in a letter and never in an email.
Kathryn said she started using the semicolon unconsciously, and hers is the only explanation I can imagine for the widespread incorrect use of the semicolon in salutations.
Here’s the correct punctuation: a comma for a personal letter, a colon for a business letter, and either punctuation mark in an email. (The colon is formal.) But remember: Dear isn’t required in email, even when writing to a stranger. Try one of these two openings if you want to sound professional without using Dear:
Hello, Ms. Gaertner-Johnston.
Ms. Gaertner-Johnston, I found your website, and . . .
If you want to sound friendly with a stranger, try these:
Hi Lynn, (English teachers don’t like this choice. They want a comma between Hi and the name.)
Lynn, thanks for the . . .
I’ve written a lot about greetings and salutations. If you want more examples, here’s a piece on salutations that I hope is helpful!
And now I’ve written enough for someone on vacation. The lightning has passed, the pavement is dry, and the pool is open again!