Most acronyms are formed from the first letter or first few letters of a series of words and are usually pronounced as words. If an acronym contains six or more letters, capitalize the initial letter and lowercase the others.





Initialisms are usually formed from just the first letters of a series of words. Generally speaking, write them following the upper- or lower-case pattern of the full term. When the full term is in lower case, they are usually separated by points.





Note, however, that the abbreviation plc (public limited company) is always written in lower case but without points.

In higher education, some initialisms representing degree studies combine upper and lower case and do not take points.



Note, too, that an initialism may take capital letters even when the full term does not.