Engineer is a category profession. It contains skills relating to the construction and operation of mechanisms and machinery, including siege engines.
An adult dwarf whose best skill is in this category, and who has accumulated ranks in other engineering skills (exactly how much is not clear) will be known as an Engineer.
Once he has achieved 'grand master' skill in one of these skills, but not in the others, he will be known by this skill.
If a dwarf has experience in only one engineer skill he will be known by his or her highest skill.
The engineering skills are: