Delta
Mathematics. an incremental change in a variable, as Δ or δ.
https://www.dictionary.com/browse/delta?s=t
What it basically means
Difference
What’s the difference….or delta?
Nothing really.
Delta is used in Science and Mathematics and signifies ‘what’s changed‘. It comes from the ‘Greeks’ – a term in science related subjects for a set of symbols denoting various mathematical meanings.
It pops up in lots of other related fields, in particular investment where Delta refers to the change in an option price given a change in the underlying security’s price.
In technology we may consider a delta as the difference between data held on two files, or the sequential difference.