In title of Ps. 80 (R.V. marg., "lilies, a testimony"), probably the name of the melody to which the psalm was to be sung.
those that shall be changed ...
Hitchcock's Bible Names Dictionary
Lilies, the name of some musical instrument, probably like a lily in shape (Ps. 45; 69, title). Some...
Easton's Bible Dictionary
(lilies). "To the chief musician upon Shoshannim" is a musical direction to the leader of the temple...
William Smith's Bible Dictionary
Lily of the testimony, the title of Ps. 60. (See Shoshannim.) ...