The most common and most likely answer to this crossword clue is the 9 letter word ORDINATES
I've seen this crossword clue in The Times
O
R
D
I
N
A
T
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S
More clues leading to the result ORDINATES
Buddy explains!
The straight part
We know that "lines" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lines = ordinates.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 ORDINATES mean?
ORDINATES noun- The second of the two terms by which a point is referred to, in a system of fixed rectilinear coordinate (Cartesian coordinate) axes.
- The vertical line representing an axis of a Cartesian coordinate system, on which the ordinate (sense above) is shown.
- To ordain a priest, or consecrate a bishop
- To align a series of objects