timber vs solid ground

timber and solid ground both are nouns.

Word	Noun	Adjective	Verb	Adverb
timber	Yes	No	No	No
solid ground	Yes	No	No	No

As nouns, solid ground is a hypernym of timber; that is, solid ground is a word with a broader meaning than timber:

Other hypernyms of timber include biome, dry land, earth, ground, land, terra firma.

timber (noun)	solid ground (noun)
a beam made of wood	the solid part of the earth's surface
a post made of wood
(music) the distinctive property of a complex sound (a voice or noise or musical sound)
land that is covered with trees and shrubs
the wood of trees cut and prepared for use as building material