Full Stop is a Punctuation marks and Punctation means the right use of the stops in a sentence. Where to use The Full Stop.
The Full Stop represents the longest pause. It is used:
(a) At the end of an Assertive or Imperative sentence:
He is a good fellow.
Put it down.
(b) After abbreviations and initials:
B.A., Ph.D., M.P., Co., Ltd., Dr.A.V.Rao, Mr. & Mrs. Milford.
When, however the abbreviation ends with the final letter of the full word some writers prefer to omit the full stops:
e.g., Mr, Mrs, Dr, St (street) St (Saint).