RA

Initialism of rear admiral, a rank in the Royal Navy.

Initialism of receptor agonist.

Initialism of republic act.

Initialism of rescue ambulance.

Initialism of research assistant.

Initialism of resident assistant: a trained student leader, within a college or university, who is given the responsibility of supervising students living in a residence hall.

Initialism of resolution advisory (a type of TCAS warning).

Initialism of restricted area: an area that only authorized people can enter.

Initialism of rheumatoid arthritis.

Initialism of right ascension.

Initialism of right atrium.

Initialism of roughness average

Initialism of Royal Academician: a member of the Royal Academy of Arts.

Initialism of Royal Academy.

Initialism of Royal Artillery: a regiment in the British Army.

Initialism of Republic of Armenia.

Initialism of Resident Advisor.

The Provisional Irish Republican Army.

Initialism of Arabicرَضِيَ ٱللهُ عَنْهُ (raḍiya llāhu ʕanhu, “may God be pleased with him”): a suffixal honorific used to honour companions of Muhammad (and by extension, the pious deceased in some usage).

Initialism of Arabicرَحْمَةُ ٱللهِ عَلَيْهِ (raḥmatu llāhi ʕalayhi, “may God have mercy on him”): a suffixal honorific used to honour the deceased.