Updated September 30, 2025
Spotlight on CMOS 8.37
A kinship name is a term that refers to a family member, whether close or distant. Such names include mom, dad, sister, brother, aunt, uncle, cousin, and so on.
Similar terms are used for people who aren’t necessarily relatives. These include words like doctor or waiter that refer to a profession, words like sir or ma’am that confer respect, and terms of endearment like honey or darling.
Whether any of these words should be capitalized will depend at least partly on the answers to two questions: (a) Does the word refer to a family member? (b) Is the word being used either in place of or as part of a person’s name?
If the answer to both a and b is yes, then the word is usually capitalized. Otherwise, whether to apply an initial capital will depend on some additional factors.
Kinship Names as Names
If you use a word like mom in place of a name, then it’s usually capitalized. Look for an article (a, an, or the) or other determiner (like my or our) before the word. If there isn’t one, it’s probably being used as a name and should therefore be capitalized.
Should we tell Mom what we did? (Should we tell Rita what we did?)
What do you mean, Grandfather? (What do you mean, Reggie?)
but
Should we tell my mom what we did?
We didn’t think of him as a grandfather.
In the first two examples above, a name could easily be substituted for Mom or Grandfather (as shown in parentheses), but in the last two examples, that would be unusual (but not impossible: My Rita is taller than your Rita; I once knew a Reggie).
Though words for parents and grandparents are more likely to be used in place of a name than other words of kinship, the same rule can be applied to other relatives referred to in this way.
What’s the rush, Sis?
Thanks, Cousin.
but
I told my sister not to worry.
Maria is a second cousin.
Many writers, however, will prefer lowercase for all but parents and grandparents (Yes, cousin). And such words used in a figurative sense are always lowercase (You’re telling me, brother). Editors can help by fixing any inconsistencies (or querying the author about them).
Kinship Names with Names
Kinship names can also be used in combination with a person’s name, but this is more common with some terms than others. Aunt and Uncle are often used in this way, usually with first names.
Where’s Aunt Betty?
but
Where’s your aunt?
The wording in the first example is so common, in fact, that the compound with Aunt is like a name unto itself. For that reason, the usual rules for using lowercase after a word like my can be relaxed, especially in fiction and other creative contexts.
Where’s your Aunt Betty?
instead of
Where’s your aunt Betty?
The capitalization in that last example (your aunt Betty) is strictly correct. But in, say, a novel or story that includes a character who is referred to by others as Aunt Betty, switching from Aunt Betty to aunt Betty when it follows my or the like might seem fussy or pedantic.
If it’s not an aunt or an uncle, however, stick to the rules. Except in certain religious contexts (e.g., Mother Teresa), words like mother and father and sister and brother are rarely used as part of a name.*
But even words that are often used with a name—including cousin and words like grandmother or grandfather—can usually be lowercased after a determiner.
Cousin Bob but my cousin Bob and my cousin
Grandma Smith but our grandma Smith and our grandma
Now let’s look at words outside of kinship, where the principles are similar.
Jobs Titles and Terms of Endearment or Respect
When a job title is used in place of a name, it is capitalized only if it might also be used as a title before the name (where it is also usually capitalized—and in some cases abbreviated).
What would Coach do? (What would Coach Bob do?)
How much will this cost, Doctor? (How much will this cost, Dr. Jones?)
but
Talk to your coach.
My grandmother was a doctor.
For an occupation that isn’t normally used as a title before a name, lowercase is the rule.
Hey, waiter, could I please have some more water?
The same goes for terms of endearment or respect.
Thanks, sweetie!
We’re ready for you, sir.
Unlike doctor or coach, such words aren’t normally used as titles.†
Summing Things Up
Words for kinship are usually capitalized when they stand in for a name (Hi, Mom; Thanks, Aunt Jo). Otherwise, they’re usually lowercased (Just ask my mom; Meet my cousin Ralph). For similar terms, follow the same pattern except for any word that isn’t normally used as a title before a name (Aye, Captain! Yes, ma’am!). Additional exceptions are noted above and in CMOS 8.37.
* Words for parents and siblings (not to mention children and spouses) are of course often used with a name whenever that name simply identifies the parent or sibling: Her sister Regina. For the use (and nonuse) of commas in such constructions, see “Your Dog[,] Smurf: Understanding Commas with Appositives.”
† One exception: Someone like Paul McCartney, who was knighted by Elizabeth II, would be Sir Paul (with a capital S); however, even the former Beatle can be referred to as sir (lowercase s) when that term is used by itself (see also CMOS 8.32).
Family art by scusi / Adobe Stock.
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