Help me my brain cant comprehend this

Answer:
The 'change of'.
Explanation:
So basically think delta as a prefix for a word and delta means change of. So if we are looking for delta (v), then that means we are looking for the change of the velocity. Another example is that if we are looking for delta (t), then that means we are looking for the change of the Time. You can find the change of pretty much anything and everything by using the formula ( final x - initial x ) and x equals whatever value you are trying to final the delta of. Hope this makes sense, and if you want a more detailed answer lmk.