That’s because “Δ” means “a change of” or “an interval of”. So, Δt is “an interval of time”. It is like a compound word, really. It conveys more information tha

That’s because “Δ” means “a change of” or “an interval of”. So, Δt is “an interval of time”. It is like a compound word, really. It conveys more information than giving it an arbitrary, single-letter name. This convention is used in a whole bunch of scientific fields, like quantum mechanics, chemistry, biology, mechanics, thermodynamics, etc. It’s also very useful in how it relates to derivatives, which is a crucial concept in just about any kind of science you could care to mention. So yes, there is a learning curve, but we write things this way for good reasons, most of the time. Multiplication should be represented by a (thin) space in good typography, to avoid this sort of things. Not doing it is sloppy and invites misreading. Same with omitting parenthesis around a function’s argument most of the time (e.g. sin 2πθ instead of sin(2 π θ) ).