(lilies). "To the chief musician upon Shoshannim" is a musical direction to the leader of the temple choir which occurs in (Psalms 45:1; 69:1) and most probably indicates the melody "after" or "in the manner of" (Authorized Version upon") which the psalms were to be sung. Shoshannim-eduth occurs in the same way in the title of (Psalms 80:1) ... As the words now stand they signify "lilies, a testimony," and the two are separated by a large distinctive accent. In themselves they have no meaning in the present text, and must therefore be regarded as probably a fragment of the beginning of an older psalm with which the choir were familiar.
Smith’s Bible Dictionary
Shoshannim
Smith’s Bible Dictionary, William Smith (1863). Public domain, from the CrossWire SWORD module.