The word dramaturg originates from the ancient Greek: δραματουργός
dramatourgos=drama (deed or act) + ergos (work or composition)
So, originally the dramatourgos meant a composer of action, i.e. the playwright. Although this expression for a playwright was rarely used.
The word dramaturgia in the early modern times referred to a compilation of play synopses.
The role of the dramaturg emerged in 1767, when the playwright Gotthold Ephraim Lessing (1729-1781) was employed by the Hamburg National Theatre to be an ‘in house critic’ for all their productions. Lessing's thoughts on curating for a public theatre and nurturing new drama can be read in the 104 volumes of his Hamburg Dramaturgy. It was Lessing's choice of the word that launched the meaning of the word dramaturgy in the sense of composition of a piece of theatre. From his appointment we also count the beginning of the profession of the dramaturg.
The dramaturgy of any performance piece (whether theatre, dance or an installation performance) is the dynamic structure built from its various components: words, physicality, music, lights, sound, space and the audience's engagement. It is also how those components relate to the experience of the work as a whole.
The dramaturg is a member of the creative team engaged in a dialogue relationship with the artists (and the company/theatre/festival) to help them find their own artistic journey through the process in order to fulfil their artistic vision. It is a collaborative role.
The dramaturgical process of a piece ('doing dramaturgy') is a critical engagement with the work’s composition in order to develop and realise it. This is often achieved by combining the skills, knowledge and decisions of the artistic team.