ABSTRACT
The principal use of the full stop or full point (called a period in the USA) is to signal the end of a declarative or imperative sentence (that is, a sentence that makes a statement or that issues an instruction):
Use a full stop also after a parenthetic statement that forms a complete sentence between other sentences:
8.2 Marking titles, abbreviations and acronyms
Do NOT use full stops:
• after titles, headings, and sub-headings;
• after units:
• within capitalised abbreviations or acronyms:
Use full stops between letters in lower-case abbreviations. Do not use e.g. and i.e. at all (see pages 51 and 101):
Use full stops after abbreviations formed by truncation (cutting off the end of the word), except after abbreviations of units:
In correspondence, use a full stop after an abbreviation of a personal title or of a place name, except when the abbreviation contains the first and last letters of the abbreviated word:
In correspondence, the contracted form of the words Public Limited Company is sometimes written in capitals without internal stops and sometimes without a final stop:
Once again, my main advice is that you should be consistent. Abandon the guidelines given in this section if your organisation’s house style differs from the advice given here. The most important feature of these uses of full stops should be consistency within any organisation, preferably in conformity to international standards.
