Attribute

 Description

Use

 these are the logical 'fields' or 'access points' being queried upon (title, author, anywhere....)

Relation

 operators defining how a field should relate to the query term in order to be considered as a match (=, >, sounds like...)

Search Term

 the actual search term can be entered here.

Position

 what position in the field should the term be in for it to be a match (anywhere in the field, at the start of the field...)

Structure

  the structure of the value being passed in the query (should it be treated as a phrase, a word, a number... this may change the logic of the search)

Truncation

 how a search term is used - as part of a word (forming the beginning, middle or end of a word) - or the whole word. This can be set for any combination of the above.

Completeness

 should truncation be applied to the query value, and if so how.