The phrase 'initial capital letters' is correct and usable in written English.
The phrase is typically used when referring to words or items in a list which start with a capital letter. Example: All of the names in the list must be written with initial capital letters.
Who affixes glorious names to acts of Congress -- with words whose initial capital letters spell out a hard-selling acronym?
This passage illustrates Saramago's idiosyncratic way of presenting dialogue, running the speakers together without indentations or quotation marks, the change of speakers indicated by initial capital letters.
The algorithm is divided in ten steps coded by corresponding routines identified by an initial capital letters from A to K in the routine name.
Correction 18/10/10 Though Germaine Greer filed her copy with them intact, the Latin genus names were printed without their initial capital letter.
In German, all nouns take an initial capital letter, so even a bungalow wall is a Mauer with a capital M. In English, there are many walls, but only one Wall.
If Cleave's publishers argue that the boots in question were named after the Duke of Wellington, and should therefore take an initial capital letter, their books are likely to resemble alphabet soup in which Chauvinistic, Machiavellian characters wearing Bloomers, Leotards and Cardigans, perhaps with Raglan sleeves, enjoy Sandwiches.
I don't know if the iPhone has always interpreted two quick taps on the space bar as a period and start of a new sentence complete with initial capital letter, but I found out the other day that it does just that.
Both words and pseudowords were printed with an initial capital letter to match the visual characteristics of German nouns.
We denote the family names in italic with an initial capital letter to avoid possible confusion with for example, the rhodopsin receptor.
To avoid possible confusion in subsequent paragraphs, a whole family is denoted using the corresponding family name in italics with an initial capital letter (Rhodopsin), while the homologs/members of a particular family are denoted as Rhodopsins or Adhesions or Adhesion-like receptors.
After a series of initial denials in capital letters on Twitter and more than an hour after his speech was due to start, Trump launched into an hour-long attack on the media and female accusers he called "horrible, horrible liars".
