Maths

• Closed-form expression
  Closed-form expression
  In mathematics, an expression is said to be a closed-form expression if it can be expressed analytically in terms of a bounded number of certain "well-known" functions...
  
  , a finitary expression
• Closed differential form, a differential form with the property that

Poetry

• In poetry analysis
  Poetry analysis
  and content, in an informed way, with the aim of heightening one's own and others' understanding and appreciation of the work.The words poem and poetry derive from the Greek poiēma and poieo . That is, a poem is a made thing: a creation; an artefact. One might think of a poem as, in the words of...
  
  , a type of poetry that exhibits regular structure, such as meter or a rhyming pattern;
• Trobar clus
  Trobar clus
  Trobar clus , or closed form, was a complex and obscure style of poetry used by troubadours for their more discerning audiences, and it was only truly appreciated by an elite few. It was developed extensively by Marcabru, but by 1200 its inaccessibility led to its disappearance...
  
  , an allusive and obscure style adopted by some 12th-century troubadours.