The most common and most likely answer to this crossword clue is the 5 letter word STAVE
I've seen this crossword clue in The Guardian
S
T
A
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More clues leading to the result STAVE
- Run into pole — fast!
- Verse, in poet, looking back, not his first? Could be
- Two ways to make musical lines
- Piece of wood to recover? About time!
- Notes written here in Home Counties about tax return
- Staff in more ways than one
- A vet’s arranged place for notes
- A couple of small streets’ staff
- Staff hitting one small road after another
- Staff to cut costs? About time
Buddy explains!

The straight part
We know that "musical lines" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case musical lines = stave.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does STAVE mean?
STAVE noun- One of a number of narrow strips of wood, or narrow iron plates, placed edge to edge to form the sides, covering, or lining of a vessel or structure; especially, one of the strips which form the sides of a cask, a pail, etc.
- One of the bars or rounds of a rack, rungs of a ladder, etc; one of the cylindrical bars of a lantern wheel
- A metrical portion; a stanza; a staff.
- The five horizontal and parallel lines on and between which musical notes are written or pointed; the staff.
- A staff or walking stick.
- A sign, symbol or sigil, including rune or rune-like characters, used in Icelandic magic.
- To fit or furnish with staves or rundles.
- (usually with 'in') To break in the staves of; to break a hole in; to burst.
- (with 'off') To push, or keep off, as with a staff.
- (usually with 'off') To delay by force or craft; to drive away.
- (rare or archaic) To burst in pieces by striking against something.
- To walk or move rapidly.
- To suffer, or cause to be lost by breaking the cask.
- To render impervious or solid by driving with a calking iron.