The third Monday in January is the day we celebrate Martin Luther King Jr.’s birthday–Martin Luther King Jr. Day. With every multi-word proper noun, there are potential errors for capitalizing and punctuating.
This is the case with today’s holiday as well, especially since it has some words that are three words or fewer (potentially indicating we should not cap them, depending on where they fall within the proper noun). It has an abbreviation (Jr.), which makes for a potential difficulty with the period (or not) and even a comma (since many incorrectly think it should be written Martin Luther King, Jr {with a comma}).
So how about a little capitalization, proper noun, punctuation lesson to start the week off right? According to the Associated Press Style Book and the Chicago Manual of Style, this holiday should be written as follows (my notes below that):
Martin Luther King Jr. Day:
1. Proper nouns, including holidays, should be capitalized.
2. A proper noun containing two or more words should follow these capitalization rules:
a. Capitalize the first and last word regardless of those words’ lengths: Fourth of July, Training for Triumph, Ode to Joy
b. Capitalize any internal words of a proper noun that are four letter or longer: World Book Encyclopedia
c. Capitalize any internal words of a proper noun that are three words or fewer if they are not one of the following:
i. Prepositions: Ode to Joy (NOT cap the prep to)
ii. Articles/Noun Markers: “For the Beauty of the Earth”
d. Capitalize any internal words of a proper noun that are three words or fewer if they are important to the title, regardless of the part of speech:
i. “This Is My Father’s World” (Is=linking verb important to title; My=pronoun important to title)
ii. Martin Luther King Jr. Day (Jr. is important to title)
3. Capitalize Day in this holiday because it is part of the official title of the holiday (whereas Christmas day is not since day is not really the holiday’s name).
4. Write Jr. with a capital J, lower case r., period following it–and no comma anywhere. As one of my handbooks tells it: Names do not contain commas!
5. Also note that the official holiday does not have Rev. or Dr. as part of it, though those are titles given to him. Neither one is given in the holiday (just like General or President is not used in George Washington’s Birthday). (That holiday is also called Presidents’ Day.)
6. Lastly, note that this holiday is also called Martin Luther King Day (with no Jr.).
Now you know how to write and punctuate Martin Luther King Jr. Day. Hope it’s a good one!