United States Navy staff corps

[7] The insignia of an oak leaf and acorn was adopted in 1830 to signify members of all staff corps then in existence, which included doctors and pursers.

[8] The Medical Corps was formally founded in 1871,[9] and after several design changes, in 1894 symbols resembling the modern insignia were adopted.

The staff corps insignia has evolved to include, as of 2019, four faith symbols: the Christian (Latin) cross, the Jewish Star of David and tablets, the Muslim crescent moon, and the Buddhist wheel of law.

In 1948, female Naval officer uniforms were standardized using the current corps insignia.

The chiefs of the Civil Engineer, Chaplain, and Judge Advocate General's Corps were the first women to hold those posts.

Despite the name, their specialties were not limited to mathematics, but included astronomy, engineering, justice, and the teaching of foreign languages.

[15] They were conferred relative rank in 1863, and in 1866 their insignia was defined as a silver live oak leaf and an acorn.

[8] The corps' dissolution was the result of their own efforts in training line officers who would replace them, making civilian appointments as professors unnecessary.

[15] The Naval Construction Corps was established and assigned relative rank in 1863, before which they were civilians.

The (fourth) digit (X) denotes whether the officer has a Regular (0), Reserve (5), or Full Time Support (7) commission.