In your linked definition are " Time series forecast", " cross-correlation", " stochastic","moving average"," doubly stochastic",and " Fourier transform": All of these are indicators.
"Seasonality", and (news~) "economic activity" perhaps are for multiple types of chart study.
"Trend estimation" and "patterns", while for anything, are especially broken down price action.
Drawing devices on price action begin to show what I mean -- They may be implied or even used, but I don't see them in the definition you linked to nor in the few links I explored within that definition. Not only do these devices begin to structure a chart in a spatial-analysis way, traders use them in a way that reveals that (from the thoughts of a person not educated formally in this field)
-- scientists have the stuff they perform data on, and so are more inclined to go for their reality than that of the chart's
-- mathematicians both make stuff from the charts and have the charts serve the stuff's purpose
-- traders only have the charts (if chart technicians only and also), and so treat the charts as if only they count.
Thus, traders further the study of charts, as well as borrow techniques from the pure sciences.
One thing traders (or at least this would-be trader) also borrow and recombine is the idea of spatial analysis used in time series analysis.
You can easily dismiss this as hogwash. It can also serve as a grain of truth to further understanding.
P.S. -- Yeah, whoops, trading is something different.