Amber is also a recognized color, as in the phrase "it was an amber colored wine" and etc.
So, references are quite difficult in some cases, especially due to translation and transliteration problems.
PE
You are right PE that definitions can be fluid and non-clear. Actually, it seems there is a multitude of terms being used for the different types of hardened resin used to create oil painting varnishes. Besides
amber are
dammar/damar, copal, mastic, rosin/colophonium and
resin/gum terms often used and apparently intermingled, although in general, some of the terms are rather specific for a certain type of resin.
As an general overview to be taken "with a pinch of salt":
- Amber for fossilized hardened resin of often unclear origin
- Copal generally seems to be a synonym for the term "amber" as described in the sentence above.
-
Dammar/Damar for resin from
Dipterocarpaceae tropical trees from primarily India and Asia. This is a large family of different tree species (+/- 500 different species) belonging to the normal broad leaf flowering trees like oak, beech etc.
- Mastic seems be hardened resin from a specific broad leaf evergreen shrub:
Pistacia lentiscus
-
Rosin/colophonium for hardened resin extracted from pine trees.
- Resin and gum seem synonym, and seem general terms for the fluid extracted from trees, both still in its fluid, as well as hardened state (the resin polymerizes, probably in combination with oxygen from the air)
Again, the terms are often intermingled, and most of these resin types have other uses as well, for example in printing inks. In addition, chemically/synthetically created resins seem to have largely taken over the market for varnishes, probably both due to cost, and better characteristics (less yellowing, more robust).
Marco