Understanding \ts output

Hi,

I see that many people are using the system command “\ts” wherein I understand the meaning of \t (the first output out of list of two values) but I do not understand the meaning of second output. From references I can see that it means “time and space of expression” but I do not understand “space of expression”. Can anybody explain please?

thank you.

http://code.kx.com/wiki/Reference/SystemCommands#.5Cts_exp_-_time_and_space

“space” meaning memory usage