Stentato
Stentato or stentando is a musical expression which means "labored, heavy, in a dragging manner, sluggish", or "strong and forced". It is abbreviated "sten." or "stent." and is, for example, the direction given for the last 17 bars of the Sanctus of Giuseppe Verdi's Requiem and also used by Ottorino Respighi in his composition Pini di Roma.
Sometimes the term Stentate is used as well. This has the same meaning as Stentato or stentando.