vade mecum
Concise Oxford English Dictionary © 2008 Oxford University Press:
vade mecum /ˌvɑːdi ˈmeɪkəm, ˌveɪdi, ˈmiːkəm/
▶noun a handbook or guide kept constantly at hand.
– origin C17: mod. L., lit. ‘go with me’.
'vade mecum' also found in these Oxford entries:

