What do the thermal resistance suffixes in Rth(j-c), Rth(j-a) and Rth(ch-c) mean?

As an example for TO-220 (cross-section)

In the Rth(j-c), Rth(j-a) and Rth(ch-c),
“j” means a “junction”
“ch” means a “channel”
“ch” is used for MOSFET
“j” is used for other semiconductor devices
“c” means a “case”. Case means “Semiconductor device's package”
“a” means a “ambient“

“Rth(j-c)” and “Rth(ch-c)” means thermal resistance of between junction and case.
“Rth(j-a)” means thermal resistance of between junction and ambient.

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