When SQL*Plus wraps the output to the next line according to the LINESIZE.
If your window is particularly wide, then you can use a wider LINESIZE, avoiding the wrap.
SQL>
SQL> --
SQL>
SQL> show linesize
linesize 300
SQL>
SQL> set linesize 3
SQL>
SQL> select rownum, object_name
2 from all_objects
3 where rownum < 20
4 /
SP2-0253: data item 1 ("ROWNUM") will not fit on line
SQL>
SQL> set linesize 300
SQL>
SQL> select rownum, object_name
2 from all_objects
3 where rownum < 20
4 /
ROWNUM OBJECT_NAME
---------- ------------------------------
1 ICOL$
2 I_USER1
3 CON$
4 UNDO$
5 C_COBJ#
6 I_OBJ#
7 PROXY_ROLE_DATA$
8 I_IND1
9 I_CDEF2
10 I_PROXY_ROLE_DATA$_1
11 FILE$
12 UET$
13 I_FILE#_BLOCK#
14 I_FILE1
15 I_CON1
16 I_OBJ3
17 I_TS#
18 I_CDEF4
19 IND$
19 rows selected.