doctor and doctor of medicine); these are not considered doctoral degrees. abbreviation doctor is abbreviated "dr" in british english and "dr." in north american english. the plural abbreviation is "drs". british usage in british english it is not necessary to indicate an abbreviation with a full stop after the abbreviation, when the first and last letters of the abbreviation are the same as for the unabbreviated word, i.e. the abbreviation is a contraction, as in the case for "doctor". in the united kingdom, it is normal also to omit stops from postnominal letters, thus the usual abbreviation for "doctor of philosophy" is "phd" (or "dphil", where this is used). the fully punctuated "ph.d." or "d.phil." is anachronistic and, where the abbreviated form of the degree is defined by regulation rather than custom (e.g. oxford), may be technically incorrect. american usage american english makes no distinction between abbreviations that are contractions and abbreviations that are not. a period is used: the abbreviation of doctor is usually written as "dr." in north america. however, the us postal service prefers punctuation to be omitted from addresses. honorary doctorates an honorary doctorate is a doctoral degree awarded for service to the institution or the wider community. it may also be awarded for outstanding achievement in a particular field. this service or achievement does not need to be academic in nature. often, the same set of degrees is used for higher doctorates, but they are distinguished as being honoris causa: in comprehensive lists, the lettering used to indicate the possession of a higher doctorate is often adjusted to indicate this, for example, "hon scd", as opposed to the earned research doctorate "scd". the degrees of doctor of the university (duniv) and doctor of humane letters (dhl), however, are only awarded as honorary degrees. by convention, recipients of honorary doctorates do not use the title "dr" in general correspondence, although in formal correspondence from the university issuing the honorary degree it is normal to address the recipient by the title. however, this social convention is not always scrupulously observed; notable people who defied social convention and used the honorary prefix include: benjamin franklin, who received honorary master's degrees from harvard and yale in 1753, and from the college of william and mary in 1756, and doctorates from the university of st andrews in 1759 and the university of oxford in 1762 for his scientific accomplishments. he thereafter referred to himself as "doctor franklin". maya angelou, who held many honorary doctorates, called herself and was referred to by many as "dr. angelou" despite holding no undergraduate or advanced (non-honorary) degree. booker t. washington was often referred to as "dr. washington" after receiving an honorary doctorate from dartmouth college. sukarno, president of indonesia, was awarded twenty-six honorary doctorates from various international universities including columbia university, the university of michigan, the university of berlin, the al-azhar university, the university of belgrade, the lomonosov university and many more. and also from domestic universities including the universitas gadjah mada, the universitas indonesia, the bandung institute of technology, and the universitas padjadjaran. he had often been referred to by indonesian government at the time as 'dr. ir. sukarno', combined with his degree in architecture (ir.) from bandung institute of technology. sukarno is the president with the highest number of honorary doctorates in the world. author and lexicographer samuel johnson, who had some years earlier been unable (due to financial considerations) to complete his undergraduate studies at pembroke college, oxford, was awarded the degree of master of arts by diploma in 1755, in recognition of his scholarly achievements. in 1765, trinity college dublin awarded him the degree of doctor of laws and in 1775 oxford bestowed upon him the degree of doctor of civil law by diploma. he never referred to himself as "dr. johnson", even though a degree by diploma is distinct from an honorary degree, but it was used by his contemporaries and in his biography by james boswell. other uses of "doctor" in some regions, such as the southern united states, "doctor" is traditionally added to the first name of people holding doctorates, where it is used in either direct or indirect familiar address. "doc" is a common nickname for someone with a doctoral degree, in real life and in fiction — for example, the gunfighter doc holliday, the australian politician h.v. "doc" evatt, the character "doc" in gunsmoke, and pulp hero doc savage. in roman catholicism and several other christian denominations, a doctor of the church is an eminent theologian (for example, saint thomas aquinas, also known as the angelic doctor) from whose teachings the whole church is held to have derived great advantage. african leaders often refer to themselves as "doctor" as part of their title upon assuming office.