Noun

(wikipedia expertise) (-)

Great skill or knowledge in a particular field or hobby

The scientist has expertise in the field of nuclear fusion.

* 2014 , Michael White, " Roll up, roll up! The Amazing Salmond will show a Scotland you won't believe", The Guardian , 8 September 2014:

He spoke of Scotland's hydroelectric projects in Africa, local expertise shared with the world's poor.

advice, or opinion, of an expert

Noun

(uncountable) The practical aspects of a given art, occupation etc.; formal requirements.

* 1924 , HE Wortham, A Musical Odyssey , p. 97:

Brahms, after realizing that the technique of the piano was developing along mistaken lines, and his own danger of stereotyping his style, keeps away from it for most of his middle age [...].

* {{quote-magazine, year=2013, month=July-August, author= Catherine Clabby

, magazine=(American Scientist), title= Focus on Everything , passage=Not long ago, it was difficult to produce photographs of tiny creatures with every part in focus. That’s because the lenses that are excellent at magnifying tiny subjects produce a narrow depth of field. A photo processing technique called focus stacking has changed that.}}

(uncountable) Practical ability in some given field or practice, often as opposed to creativity or imaginative skill.

* 2011 , "Bhimsen Joshi", The Economist , 3 Feb 2011:

Yet those who packed concert halls to listen to him sing, as Indians did for over six decades, rarely mentioned his technique .

(label) a method of achieving something or carrying something out, especially one requiring some skill or knowledge.

* 2011 , Paul Lewis & Matthew Taylor, The Guardian , 16 Mar 2011:

They said executives were warned about one technique nicknamed "carpet karaoke", which involved bending deportees over in aircraft seats to silence them.