halla: forest, specifically a tamed forest used for dwelling, silviculture, lumbering, coppicing, hunting, parkland, etc. Oppose loth.
loth: forest, specifically wild forest not used for any purpose. Oppose halla.
(Note that this is a very important distinction on Eliéra, which has a lot of forest cover, and it is important to make the distinction between the forests where, when lost, you're likely to be eaten by a grue and those in which you're likely to be given dinner and escorted home.)
opaïs: flower/blossom/bloom, floral.
This is a companion discussion topic for the original entry at https://eldraeverse.com/2024/12/09/eldraeic-words-of-the-day-3