stih

1. line of verse
   Prvi stih te pesme znam napamet. — I know the first line of that poem by heart.
2. (in plural) verses; poetry; lyrics
   On piše stihove još od gimnazije. — He has been writing poetry since high school.
   Stihovi ove pesme su baš tužni. — The lyrics of this song are really sad.

A whole poem is "pesma", not "stih".