Dictionary:

enjambment

  (ĕn-jăm'mənt, -jămb')

The continuation of a syntactic unit from one line or couplet of a poem to the next with no pause.

[French enjambement, from Old French enjamber, to straddle : en-, causative pref.; see en–¹ + jambe, leg; see jamb.]

enjambment or enjambement, the running over of the sense and grammatical structure from one verse line or couplet to the next without a punctuated pause. In an enjambed line (also called a ‘run‐on line’), the completion of a phrase, clause, or sentence is held over to the following line so that the line ending is not emphasized as it is in an end‐stopped line. Enjambment is one of the resources available to poets in English blank verse, but it appears in other verse‐forms too, even in heroic couplets: Keats rejected the 18th‐century closed couplet by using frequent enjambment in Endymion (1818), of which the first and fifth lines are end‐stopped while the lines in between are enjambed.

A thing of beauty is a joy for ever:
Its loveliness increases; it will never
Pass into nothingness; but still will keep
A bower quiet for us, and a sleep
Full of sweet dreams, and health, and quiet breathing.

The continuation of the sense and therefore the grammatical construction beyond the end of a line of verse or the end of a couplet.

The noun has one meaning:

Meaning #1: the continuation of a syntactic unit from one line of verse into the next line without a pause
  Synonym: enjambment