A pseudo-variable which controls where in memory the dynamic data structures are to be placed. The default is TOP, the first free address after the end of the program.
LOMEM=LOMEM+100 PRINT ~LOMEM :REM The ~ makes it print in HEX.
Normally, dynamic variables are stored in memory immediately after your program. (See the appendix entitled Format of Program and Variables in Memory). You can change the address where BBC BASIC (Z80) starts to store these variables by changing LOMEM.
USE WITH CARE. Changing LOMEM in the middle of a program causes BBC BASIC (Z80) to lose track of all the variables you are using.