SIDSPACE

 
SIDSPACE is a mnemonic used in remembering which Latin prepositions take the ablative case. 
SIDSPACE stands for the following prepositions: sub (during), in (at), de (about), sine (without), pro (before), ab (after), cum (with), and ex (from). Although not all of these words take the ablative case in every context, all of them do take it some of the time. For example, 'in' takes the ablative case when expressing location, as in "He is in Italy," but takes the accusative case when it is expressing motion, such as "He went into Italy."
The mnemonic omits some of the less common prepositions, which are included in the rhyme:
A second version goes as follows:
A third version is as follows: